#precalculus

1 messages · Page 13 of 1

wraith sequoia
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🙂

viscid thistle
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u might if ur dad is rich

slow coral
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it's good to aspire

viscid thistle
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or u are super talented

wraith sequoia
slow coral
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chain rule i'd imagine

wraith sequoia
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idts

slow coral
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idk i didnt read the full question

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dy/dx = du/dx * dy/du

viscid thistle
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plus u need to bring in olympic medals

grave swallow
wraith sequoia
slow coral
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you use chain rule when you're differentiating composite functions

wraith sequoia
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medals

slow coral
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if you're trying to differentiate gf(x) then you'd set u to f(x) and y to g(u)

wraith sequoia
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oh

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I hope I become a single digit ranker

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how much does one need for iit bombay computer science?

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double digit

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Because I'm a tech nerd, math nerd, science nerd, so, I love Computer Science

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yeah

grave swallow
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ur bio

wraith sequoia
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student loan maybe

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idk much about that

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My dream is to get in NASA

wraith sequoia
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if I ever even going to

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Nope, accredited institutions only

slow coral
wraith sequoia
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you need US citizenship well

slow coral
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probably one of my favourite bands ngl

wraith sequoia
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you know why

grave swallow
forest fern
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can someone give me a precalc prob, im going to ap precalc next yr and i wanna see what its like

marble leaf
forest fern
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i did but i dont know which is beginning and which is harder

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ok ty

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is that rsm

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lmao

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13c3

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so 13211

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13x2x11

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286

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is it 286

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@viscid thistle

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hmm

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is it a permutation..?

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its um

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286*6

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so

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1716

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i think idk

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lol ty

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ty

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ruh roh

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is that ap?

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damn it

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im about to be a freshman

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ty lol

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alr gimme all the rsm

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teamwork makes the dreamwork fr

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idk

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send me some

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yes

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like 5-10 problems

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ill help u

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mhm

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ill try to do them

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in dms

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fr

viscid thistle
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anyone know types of cardinals?

forest fern
viscid thistle
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inaccesible cardinal

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mahlo cardinal

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a true infinity

forest fern
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what is that 😭

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okay

viscid thistle
forest fern
viscid thistle
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its useful for power scaling

forest fern
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yes dawg ill do like 5 problems 😭

viscid thistle
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also do you guys know what set theory is?

forest fern
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kinda

viscid thistle
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Cool i joined this server to understand such things as that, i want to scale goku's cosmology using mathematics

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yk who goku is right

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yes

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yessir

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The living world in db countains all sets of mathematics, including set theory and cardinals

slow coral
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sdbh zamasu 🤮

viscid thistle
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in dbs

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he got nerfed in dbh tho

forest fern
terse thicket
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Is tangent the length of the hypotenuse on a triangle in a unit circle

flint bloom
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it’s the ratio of the height of the triangle to the length of the triangle

granite goblet
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frfr

old isle
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think of its derivative

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whats the derivative of e^x?

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and for e^(x/2), we generally apply u-sub to x/2 and it follows from there

grave swallow
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i think he means substitution rule

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like

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chain rule

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but

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vice versa

spice yoke
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can somebody help me solve this partial derivative?

shy vine
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this is just a regular derivative

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to see this $z' = 2\sin(x+2) = 2\sin(z+2)$ or $\pdv{z'}{z} = \pdv{z'}{x}$

obsidian monolithBOT
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ForJoke

grave swallow
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derivative of a function is e^x. if we define the unknown function as c^x we can conclude that (c^x) * ln(c) = e^x. (ln(e) = 1) hence the unknown function is e^x it self.

spice yoke
spice yoke
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can somebody help me solve this partial derivative?

shy vine
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technically this is 0

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because 2sin(6) is a constant

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and the derivative with respect to a number doesn't really make sense

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unless you are saying that 2 is a symbol and not a number

spice yoke
shy vine
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Are you trying to find the derivative at 4?

spice yoke
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no that would be zero you brought up a good point tho

shy vine
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derivative at 4 is not 0

slow coral
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integration by substitution is like doing the chain rule but worse in every way

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because you have to restate the integral in terms of u

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and its sometimes extremely vague how you should do that

spice yoke
shy vine
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sorry Im confused of what your question is

spice yoke
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no its allright I have also formulated it wrong and mixed things up, but I finally understood my problem and managed to get a better grip on it

forest fern
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yo who got some beginner precalc

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they dont understad

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we can work together

olive tapir
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hey, how can I get help for precalculus?

willow bear
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by posting the question(s) you need help with

spice yoke
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Yo is this correct what I have done here?

glad jetty
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looks good

spice yoke
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nice

spice yoke
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idk, but I would have loved to study in sweden they appereantly have great education system

marble leaf
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The math SAT is not too difficult. It is a standardized test that is designed to be balanced regarding the general population, so don't mistake it for the hardest math problems. That said, I do feel like the average US math curriculum for grades 1 to 12 is mediocre compared to math systems in certain other countries, although colleges are a different story.

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There are many top colleges in the US, so completing a graduate course in the US is a decent option.

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It depends what college tho

forest fern
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math SAT is hella easy

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trust

marble leaf
forest fern
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fair

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its j alg 1

marble leaf
# forest fern its j alg 1

Algebra 1 is sort of the introduction into higher-level math, so it isn't supposed to be very hard. I would say the difficulty begins with integration, but it's different for everyone.

forest fern
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difficulty is trig imo

marble leaf
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I haven't taken integration yet but I've heard that a lot of people struggle with it.

marble leaf
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So I can see how it could be difficult to wrap your head around.

forest fern
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should i take multivariable?

marble leaf
forest fern
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wbu

marble leaf
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Or even 10th

forest fern
marble leaf
forest fern
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ye

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which grade u in

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dang u typing an essay

marble leaf
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I'm about to finish 8th grade and I've completed everything up to alg 2. I haven't taken precalc yet but I have experience with limits, derivatives, and other calc topics so I think I'll be fine.

marble leaf
forest fern
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dang same

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lowkey thought you were a junior or something

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lol

marble leaf
forest fern
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lmao

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what are u takin next year

marble leaf
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I think precalc will be quick for me so I might be able to unofficially take mv calc in 11th or 12th

marble leaf
forest fern
marble leaf
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Lol

forest fern
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W

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same

marble leaf
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I might go for a math degree in college along with a cs degree or something

stuck python
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a few kids in my school did it too, calculus in general is actually easier than algebra in many respects

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at least calculus 1, assuming conceptual parts of math are not something you struggle with

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Plus the added advantage of taking calculus as an AP course in highschool is you get a whole year to digest the concepts and be able to work with them, rather than in university where you are only given half a year (or less depending on how semesters go) so in a lot of respects you will actually learn it better

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that is, assuming you are being taught just as well in both cases

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highly recommend you do it if you aren't struggling right now in mathematics, if anything use this discord. I certainly wish I had something like this going through school

forest fern
forest fern
marble leaf
# oblique root Wdym unofficially

I meant that it's not counted by the school system when I skip levels after taking them outside of school, so in the school system I'm restricted to taking precalc next year.

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Basically since the highest level of math I've taken in school is alg 2, I can't take calculus for example next year, I'm restricted to precalculus. Likewise, because I take one math course each year in school, even if I get to mv calculus early I still have to do the school prerequisites, which will take me 2 more years after precalc.

marble leaf
forest fern
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whos the owner of this server

stuck python
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but multivariable is very similar to calc 1

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the generalizations are very natural

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except maybe stoke's and green's theorem

marble leaf
marble leaf
forest fern
marble leaf
verbal garnet
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It's the first half of calculus 2

golden arrow
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Can someone explain to me why if we take annual compount intrest with imaginary intrest rates the capital raises significantly after 8 years ie. We get spiral but if we have same intrest rate but we compound the intrest continiously (instead of annually) we get to a circle and dont make any profit in the end

marble leaf
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Ya tbh idk if it's actually difficult or not but people have told me it is

verbal garnet
slow coral
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<@&268886789983436800>

verbal garnet
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Mods are asleep I guess

slow coral
verbal garnet
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They were

marble leaf
verbal garnet
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Of course.
I don't blame them for anything

hushed sphinx
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Sheesh, 3 minutes response time. Off with our heads!

verbal garnet
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More like 20 to me

warped ridge
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Actually moderation is great here compared to some other servers I'm in. Let's appreciate it

verbal garnet
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Yeah overall it's great

warped ridge
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I mean, I'm in a server with like, what, 50k members? And moderation is zero tbh.

hushed sphinx
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The modping shows at :43 for me, logs clock the ban and cleanup at :46.

warped ridge
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Well uh mods have a life too.

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They aren't living just to moderate the server

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So pretty much understandable even if it takes more than that.

slow coral
warped ridge
slow coral
elder marten
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equation of circle: (x-a)^2 + (y-b)^2 = r^2
where the centre is (a,b) and the radius is r

marble leaf
verbal garnet
gloomy tide
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is it always necessary to check the solution of radical equation ?

summer ruin
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it is when you make non-equivalent transformations, yes

gloomy tide
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@summer ruin what do u mean by non-equivalent transformation?

summer ruin
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applying functions which are not monotone

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ln(x) > ln(y) if and only if x > y, provided x and y are positive numbers, meaning given the inequality x > y it is equivalent to stating ln(x) > ln(y), so it stating ln(x) > ln(y) implies that x > y

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x > -5 and x^2 > 25 are not equivalent

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same thing work for equations, the equation ln(x^2) = 1 and 2 * ln(x) = 1 are not equivalent because ln(x^2) is defined for all non-zero x, while 2 * ln(x) is defined only for positive x

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the equation sqrt(x) = 5 - x is not equivalent to x = (5-x)^2

lunar copper
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hi

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i finished 10th rn

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and i wanted to revise precal in summer

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is there a certain way in which i should approach the topics under it

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for example matrices first, and then idk

viscid thistle
lunar copper
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yes

viscid thistle
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ITF?

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inverse trig

lunar copper
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sin inverse?

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tan and cos --

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yeah

viscid thistle
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full?

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if yes

lunar copper
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what does full include

viscid thistle
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then you may study matrices but it doesn't come under pre calc

viscid thistle
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till where have u studies?

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basic graphs and all?

lunar copper
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quadratic equations represented on graphs

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finding roots

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vertex form

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and all that stuff

viscid thistle
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i mean

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in inverse trig

lunar copper
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not sin, cos and tan graphs

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though

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our school didnt teach us trig function graphs

viscid thistle
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study trigo graphs and inverse trigo functions

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properly

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it's imp

lunar copper
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inverse trigo is

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sin^-1

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right

viscid thistle
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yeah

lunar copper
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isnt that easy though

viscid thistle
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but there's more than that

lunar copper
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oh

viscid thistle
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there are many properties

lunar copper
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do you know where i can learn it

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in detail

viscid thistle
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youtube or books

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whatever you're comf. with

lunar copper
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i see

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i'll check youtube

viscid thistle
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what channel would u go for?

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just asking

lunar copper
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organic chemistry maybe

viscid thistle
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i meant

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the youtube channel

lunar copper
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yeah

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thats a channel

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the organic chemistry tutor

viscid thistle
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which one are you gonna refer for itf

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oh

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oh yes i've read abt it somewhere

forest fern
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yo

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who got some precalc

cursive cairn
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<@&268886789983436800>

near flume
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Does anyone know where I can find a better explanation of the tangent and cotangents of sums section here? https://en.m.wikipedia.org/wiki/List_of_trigonometric_identities#Tangents_and_cotangents_of_sums

In trigonometry, trigonometric identities are equalities that involve trigonometric functions and are true for every value of the occurring variables for which both sides of the equality are defined. Geometrically, these are identities involving certain functions of one or more angles. They are distinct from triangle identities, which are identi...

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I'm looking for a source that gives a proof

soft cedar
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umm...

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i think youll find good info there under the precalc section and analytic trig

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hope this helps

hollow garnet
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i gotta find the convergence of this

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how

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nvm i managed to do it

near flume
near flume
near flume
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?

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A lot of the resources I find on this are aimed at just basic trig identities - I'm looking for something that covers the more the more complicated formulas I've referenced which use more advanced math

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I can't really ask in the advanced channels since they don't have a channel for trig

serene dock
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advanced identities?

near flume
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There's a formula for sin angle sum involving infinite products

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The ones for tangent and cotangent use elementary symmetric polynomials, etc.

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But I didn't find any source explaining it online other than wikipedia

hollow garnet
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how do i do the volume of a curve around an axis out of the curve?

minor lodge
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Hi!

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Can someone please assist me with 2. ?

stiff tapir
pale marlin
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Why does lim x->infinity n choose x = k for some constant k plot an ellipse on the complex plane?

hushed sphinx
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The phrasings "lim x -> infinity" and "for some constant x" don't look like they belong in the same thought.

stiff tapir
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Lmao

lunar copper
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i should be familiar with radian conversions before starting inverse trigonometry right

pale marlin
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Sorry

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Fixed

gloomy tide
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are there any study group here

summer ruin
lunar copper
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so just practice radian conversions then

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do you have any conversion practice worksheets

summer ruin
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there's nothing to practice though, π = 180°, rest of the angles can be obtained by division

lunar copper
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what about 1 degree = pi/180 radians

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and the other way around

summer ruin
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if the question involves angles which are not part of the standard trig table then the question isn't supposed to be solved analytically in the first place

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and calculator doesn't really care which angle you use - in radians or degrees, as long as you use it correctly

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so only the angles pi/6, pi/4, pi/2, pi and so on matter

summer crag
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Why is a invertible function and it's inverse always symmetric about the line y = x , also can we make a reflection of a function about the generalized y = mx+c line , and does it have like some general condition to exist (just like how the inverse of a function exist iff fof⁻¹ = I and f⁻¹of = I (this condtition is for reflection about the line y=x )) ?

stiff tapir
lunar copper
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ive never heard of that 😢

summer ruin
lunar copper
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what the...

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i really need a baseline from where i should start learning

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someone told me to do inverse trig before doing differentiation and i needed radians before inverse trig

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now im dying

wanton vector
wanton vector
# lunar copper i really need a baseline from where i should start learning

Depending on how much time you have (i.e. are you writing a test in a week or do you learn it just for fun and have years). If you dont have much time just start with differentiation and when you encounter some problems look them up and learn those. If you have alot of time or find yourself lost/missing alot of basics check if you can comfortably do the following:

  1. linear and quadratic functions, solving equations, Pythagorean Theorem, Quadratic Formula, polynomials in general etc.
  2. Trigonometric functions like cos(x),sin(x),tan(x) as well as exponentional functions etc.
  3. you might as well do the inverse functions too like log(x), arccos(x) etc.
    You dont necessarily need radians for those but it makes everything easier.
  4. Limits. Limits are commonly used to define differentiation and are thus useful if you want to understand whats going on.
lunar copper
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for like 2 months

wanton vector
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From the four point i mentioned, at what point are you currently?

lunar copper
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im done with the second one

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but i have to strengthen them

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and also

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i havent done any polynomials

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only problems with a degree of 2

wanton vector
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degree of 2 are also polynomials, polynomial is just the general term

lunar copper
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i see

wanton vector
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But if you study them a bit you will soon realise that if you understand linear and quadratic functions you will also soon understand any polynomial (the only thing that really changes alot is how hard it is to find the zeros of the function)

lunar copper
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quadatics is easy

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you can just

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complete the middle term

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or use formula

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i saw one of those fun polynomial videos where factorizing increases with difficulty based on the degree

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and from 2 to 3looked like a huge jump

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ive done logs but i havent really completely done exponential problems

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ive only learnt substituting x values to find y values for exponential functions

wanton vector
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For quadratics you have the quadratic formula, wich is pretty simple. For degree 3 and 4 there also exists a formula, although never taught/used in school because it is too long. Any polynomial above degree 4 doesnt have a general solution only using addition, subtraction, multiplication, division and roots

wanton vector
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@lunar copper you should probably either do exponentials, polynomials or, if you want to, start with limits and the concept of differentiation and seing whats missing like that. Introductory Videos about limits etc. often stick to simple functions that you already know so you should be able to follow those. Also that approach is more fun in my oppinion.

lunar copper
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ok i'll just revise exponential and polynomials

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also should i learn factorizing a cubic equation

wanton vector
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No. In case you need to do that just find one zero of the function through trial and error and factor it out to get a quadratic.

rigid flax
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i hate factorising cubics

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you have to try one by one

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But idk how those scientist calculate cubic when the answer is disgusting

hollow summit
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They use advance methods like newton rampson etc

slow coral
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and even then it wont get you the exact algebraic factorised form

forest fern
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my ptsd

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unit circle

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RAAAAAAAAAH

rigid flax
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will we learn that in high school

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or os it simple

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can i learn it on youtube

slow coral
#
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oh you might've meant cubic formula

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then maybe not

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not because its particularly advanced just because it's very lengthy and a bit messy

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and it's generally easier to just factorise at hs level

hollow elbow
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how to synthetic division when dividing by polynomial degree greater than 1

oblique root
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like dividing by a quadratic for ex

gray magnet
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wait i don't think that works

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what if you factorise it then divide by it's factors

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also why have i never heard of synthetic division

sleek dome
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Pls help I don't understand stand integration

hollow elbow
stiff tapir
stark quest
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why is an inverse function its reflection about y=x?

stark quest
# slow coral then maybe not

I think Grant Sanderson goes through it on the way to the quintic : https://www.youtube.com/watch?v=aaW30_f2on0&t=5135s&ab_channel=TimothyNguyen i also prefer his approach of merging completing the square and s&p over the quadratic formula

Grant Sanderson is a mathematician who is the author of the YouTube channel “3Blue1Brown”, viewed by millions for its beautiful blend of visual animation and mathematical pedagogy. His channel covers a wide range of mathematical topics, which to name a few include calculus, quaternions, epidemic modeling, and artificial neural networks. Grant re...

▶ Play video
stiff tapir
# stark quest why is an inverse function its reflection about y=x?

Given a function y=f(x). x associates an x vaule with an corresponding y vaule which is determined by the rule of the function. An inverse function of y=f(x) “undoes” this rule. Such that f^-1(f(x)) =x. The reason it reflects across the x=y access is because you are essentially changing the dependent into the independent

dense verge
#

Any tips for linear algebra? specifically proving a basis of R³

hushed sphinx
#

You'll probably want the #linear-algebra channel. (But be a bit more specific about what you need to do when you ask there).

gray magnet
#

It’s derivatives

gray magnet
#

Just use long division

gray magnet
#

It’s parts of calculus so I think you should ask somewhere else

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This is a good video though

unique sundial
#

Guys Im in 8th and I just started learning calculus. Any tips or video guides to help me?

gray magnet
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i like dis

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dis a good

unique sundial
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is it for beginners

gray magnet
#

the derivative a the fuction

gray magnet
unique sundial
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thanks!!!

gray magnet
coarse slate
#

Hello?

dreamy escarp
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hello, does anyone know any precalculus concepts that are much easier or faster if they were to be done with calculus

hollow elbow
gray magnet
pastel fossil
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Can anyone explain why my book says that the function f(x)=3(-1/2(x-1))^2+2 has a horizontal stretch of 2?

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if K=-1/2 wouldn't it just be the value of k?

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There is no explanation, it just is a 2 for some reason and I am not sure why.

gray magnet
shy vine
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triangle inequality

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since PF1F2 is a triangle, the sum of any two sides must be less than the 3rd side

slow coral
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isnt this the precalc channel

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what is this advanced mathematical sorcery

shy vine
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This does look like precalc to me

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this is just fancy geometry

slow coral
#

tf is d(P, F1)

shy vine
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distance between P and F1

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this notation is more often used for a "metric"

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although metrics are analogous to distances

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the "standard" metric is the distance we are all familiar with

barren tulip
#

in short, to prove a basis of R^3, you must prove it spans R^3, and that it is linearly independnt

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Bascially: Prove some $x \in \mathbb{R}^3$ is in the span of the potential basis, and vice versa, and also that it is linearly independent, or that there is only one linear combination of the potential basi that equals the 0 vector.

obsidian monolithBOT
#

amukh1

barren tulip
#

:D ah wrong channel shoot sorry

shy vine
barren tulip
viscid thistle
#

anyone know a good alg2 midterm practice final

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I currently have an 89.2% in the class and I need to ace this last test to end with an A

shy vine
#

2c is the third side

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d(F1, F2) = c + c = 2c

lime oasis
#

anyone know any videos or books that explain calculus to someone whos never done it before

shy vine
#

what part are you looking for?

elfin girder
#

quick q does sinx-cosx have a specific value or..

dull current
#

Hi how would you solve this?

burnt hare
#

is anyone interested in checking my work for my midterm prep packet? it’s 9 pages lol just as much as you would want to do

summer ruin
#

<@&268886789983436800>

summer ruin
#

<@&268886789983436800>

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back to back

burnt hare
#

sure yea hollup i’ll dm u

burnt hare
#

sorry i forgot😭😭

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gimme literally one second

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Yea so as much as your willing to check

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and i have several days till i need to hand the thing in too so whatevs

burnt hare
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oh it’s all good homie thanks for trying

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anyone else that wants to look at my work feel free to tell me the numbers i got wrong

patent prism
formal fox
#

check your qudratic equation

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i think it should be 9+16 under the radical

formal fox
# burnt hare

fourth page top a) check the range. it’s a parabola so it won’t be what you put

formal fox
# burnt hare

fifth image -> check your solution to the top right problem. specifically the orignal function’s domain and range

formal fox
# burnt hare

fifth image again at the very bottom. make sure you remember the formula is:
f(x)=a(x-h)^2 +k

you seem to have made the 7 into a -7 by using the logic for inside the parenthesis. remember -> this one follows the “true” sign, not the opposite sign
also - you switched you domain and range here.

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alright i’m stopping at the seventh page. hope this helped

red prism
#

What does this mean can anybody explain in a simpler language

hushed sphinx
#

,rccw

obsidian monolithBOT
summer ruin
#

absolute maximum/minimum value is unique, but points at which it is achieved are not unique

hushed sphinx
#

"Essential" in the last sentence is a rather strange word choice.

#

And it seems confusing that is speaks about "maximum and minimum values" in the first sentence and "absolute maximum or absolute minimum values" in the second -- but I can't imagine any distinction it's trying to make between those two phrasings.

shy vine
#

I guess they mean local max/min vs global max/min

hushed sphinx
#

Yeah, but that can't be it because local max/min are definitely not unique.

shy vine
#

Yeah idk what the difference is then

summer ruin
#

<@&268886789983436800>

hushed sphinx
#

(Wonderful, autodelete is glitching again).

stiff tapir
#

Why is this the channel where moderators are always pinned

uncut mulch
#

observer bias

grave forge
viscid thistle
#

Guys change the first letter of "Sigma" to L what you get?

uncut mulch
#

a <@&268886789983436800> ping

viscid thistle
smoky delta
#

This isn't the channel for that snexky

viscid thistle
warm patio
#

might be a little dumb but im doing logarithims and since they are inverses of an exponential function im thinking

a^x = y
set a = 3
x = 2
y = 9

3^2 = 9
since logarithims are inverses we flip x and y but then we get 3^9 = 2??

#

and even if we solve for y i still end up getting

y = loga(x) or 9 = log3(2)

brazen scaffold
#

logarithm is the inverse of exponential

warm patio
#

since 2 is x and 9 is y we flip them when finding inverse right

brazen scaffold
#

logarithm is just like saying
base to the what equals this number inside

#

so log 3(9) would be saying

#

3 to the what equals 9

#

so what is the answer?

warm patio
#

2

brazen scaffold
#

there you go

#

so log 3(9) = 2

#

log base (number) = exponent

warm patio
#

wouldnt the format be x = loga(y) then?

brazen scaffold
#

does that make sense yeah?

brazen scaffold
warm patio
#

x = 2

#

a = 3

#

y = 9

brazen scaffold
#

yep!

#

x is your power

#

a is your "base"

#

y is your number inside

warm patio
#

im on stewarts precalc textbook and its giving me

y = loga(x) which is where my confusion is stemming from

brazen scaffold
#

ah maybe you misread the things?

warm patio
#

even on professor leonard

#

y = loga(x)

brazen scaffold
#

aight lets thing carefully yeah

#

y = a^x

#

so a to the x = y

warm patio
#

yep

brazen scaffold
#

to find x you need to do log a on both sides

#

log a (a^x) = log a (y)

#

log a (a^x) = x

#

x = log a (y)

#

nani???

#

what is going on here?

warm patio
#

Yeah im like

brazen scaffold
#

maybe it is i making the mistake somewhere?

warm patio
#

It looks correct

brazen scaffold
#

yeah it does

#

the log rule i used as well should be corect

warm patio
#

ill just stick with x = log a (y)

#

really confused as to why they have it reversed though

brazen scaffold
#

wait hold on

#

x = log a (y)
so log a (y) means that a to the what = y
to the what is x
so a^x = y

#

we already said that tho

#

yeah no they seem slightly off

warm patio
#

Any ideas?

brazen scaffold
#

?

warm patio
brazen scaffold
#

aight let me write it down real quick

brazen scaffold
viscid thistle
#

Guys can someone explain complex numbers on my dms

#

Pls

fiery dirge
#

i can

stiff tapir
viscid thistle
#

Maths

topaz wraith
#

but the original function and the inverse "swap" their domain and range, so if inverse of f is g: Df = Rg and Rf = Dg

obsidian monolithBOT
#

Nevemlaci
Compile Error! Click the errors reaction for more information.
(You may edit your message to recompile.)

#

Nevemlaci

topaz wraith
#

@warm patio

viscid thistle
stiff tapir
viscid thistle
#

@Mode

#

<@&268886789983436800>

#

Finnaly he got banned

indigo halo
#

Does anyone know a good pre-calc (e)book?

west rune
#

How do I set up the equation for alk?

misty plover
#

for alk i guess u have to use 24000=8000*(1.17)^x

#

then x*12 to get the number of years when the city of Alk's population get triples

#

which also means that city of Bems population doubles in every (x*12) years

lunar copper
#

hi i just started learning about derivatives and came across this function in the "essence of calculus" series

#

the video said that he gave this function to the computer to look at many times between 0 and 10, and compute the distance function given "s(t)+dt", minus the value of this function t"

#

i didn't necessarily understand what he meant in this phase of the video

#

What is an "instantaneous rate of change" when change happens across time?
Help fund future projects: https://www.patreon.com/3blue1brown
This video was supported in part by Art of Problem Solving: https://aops.com/3blue1brown
An equally valuable form of support is to simply share some of the videos.
Special thanks to these supporters: http://3b...

▶ Play video
#

this was the video at 6:30 if anyone is curious

summer ruin
#

he said compute s(t+dt) - s(t) for every point t and fixed dt

lunar copper
summer ruin
#

he later adds he divided the difference by dt

lunar copper
#

all the possible values you can input into a function to get a real number output

lunar copper
summer ruin
#

sure, but it's a function of dt

lunar copper
#

wha..

#

dt is an infinitely small change in time right

#

how can it have a function

#

im sorry if i sound dumb i dont really like functions

summer ruin
#

because the set of all values of t is already predetermined, its' some segment [a;b]

summer ruin
#

if you change dt the graph that you see will change

summer ruin
stiff nebula
#

Does anyone know if this working out is correct for this question?

If not, can you please write a step by step working so I can better understand?

dark scarab
#

@stiff nebula There are somethings that are not clear, for example when you take the u substitution (correct step), the t^2 dt is transformed into du so you don't need the t^2. Also recall that coefficients can be moved outside of the integral sign

dire aspen
#

Is this really precalculus Hm

oak path
#

In Precalc, never seen that

rose rover
#

LOL this is spesh level

oak path
#

?

rose rover
#

specialist math is a math subject for the australian curriculum

oak path
#

Oh

rose rover
#

i have this formula on my formula sheet

dire aspen
#

It’s calc 2

#

Dk why they’re asking in precalc channel tho

summer ruin
#

all you have to do is compute product AB and solve a couple of equations

#

that's the point

#

why not just write general B

#

b_11, b_12, ...

#

maybe you should be open minded and actually try my suggestion

#

a matrix B with entries b_11, b_12 and so on

hushed sphinx
#

With letters.

#

So you get 8 unknowns and a bunch of equations that relate them.

summer ruin
#

the rest is just solving 4 equations for entries of B

hushed sphinx
gray magnet
gray magnet
rose rover
short saddle
#

Given x^2>=4/m^2, find the minimum value of x

gray magnet
dire aspen
gray magnet
#

Thx

autumn wadi
#

Is there any name for this "theorem"? I also don't rlly understand what it's saying

zinc fulcrum
languid schooner
#

Not sure if there is a name for your theorem.

You may think about it like this; Someone long time ago have done different problems in same shape tons of time and they already know what the solution looks like. Then they will propose that that form of solution they have come up is a "general solution".

When it comes to proving what they have is THE general solution, mathematicians often like to apply some existence-and-uniqueness-theorem to justify themselves, but that’s another story.

#

Applying method of undetermined coefficients means, you have the table of "general solution to common particular problems" in your mind already, what you need is just the accompanied coefficients to complete your solution.

#

One more classical example is partial fraction. You know how the decomposition will go already. The only thing left is solving for the unknown constants A,B,C,…

autumn wadi
#

Damn

#

Thanks, the two of ya

dapper estuary
#

Is that correct because my calculator gives me another answer

#

Or am I solving it wrong

uncut mulch
#

they made a typo, they wrote cos but they used to correct ratio in their calculations

#

you shouldn't have followed what they've written

uncut mulch
#

consider the position of x and the 100m side relative to your angle

#

relative to the given angle,
is x the opposite, adjacent or hypotenuse

dapper estuary
#

opposite

uncut mulch
#

relative to the given angle,
is the 100m side the opposite, adjacent or hypotenuse

dapper estuary
#

adjacent

uncut mulch
#

yes,

dapper estuary
#

oh

uncut mulch
#

hence what's the trig function that relates those three things,
sin, cos or tan

dapper estuary
#

it's tan

#

thank u so much ily

kindred sluice
#

Can someone confirm if I did this correctly?

desert socket
#

final answer 7pi derived r = 14

hushed sphinx
#

Right, there doesn't immediately seem to be anything that indicates the scale of the diagram.

desert socket
#

ty

hushed sphinx
#

www.parliament.uk says:

The clock dials, framed in cast iron and glazed with 312 separate pieces of opal glass, are 7m in diameter

desert socket
#

4.2m long
The minute hands are made of copper sheet 4.2m long. They weigh 100kg, including counterweights, and travel a distance equalling 190 kilometres (120 miles) a year.

#

the 4.2 translates to about 13.75 feet which i guess i shouldve then rounded to 14

#

but thats not specified.

#

the rounding at least

hushed sphinx
#

Yes, but I think those 4.2 m must include the counterweight part sticking out behind the rotation axis.

desert socket
#

gotcha.

#

The clock's gun metal hour hands and copper minute hands are 8.75 feet (2.7 m) and 14 feet (4.3 m) long respectively.

#

googling feet provides exact length

#

shouldve just googled it first time since they used a real world example

#

thanks

hushed sphinx
#

The numbers are internally consistent between 7m and 190 km:

$ calc 190000/365.2425/24/4
    ~5.41877428466475469494
$ calc 7*3.1415/4
    5.497625
$ 
dusky lark
#

if i am solving for a missing quantity such as the angle sector given theta and the radius, should i convert the the theta value to radians if they gave it to me in degrees?

granite stream
#

I am having a block regarding a question in my homework, here is the equation: e^(2x) - e^x - 132 = 0. I am quite confused as I have tried a few different ways of solving but its just not coming to me, any help would be appreciated. Does anyone have any suggestions on how to go about solving this?

#

Oh wait this may be the wrong channel, my bad

mellow kindle
granite stream
#

Thank you so much for the response. I was able to figure it out on my own but thank you again!

mellow kindle
#

Oh nice good job

dusky lark
#

how do I find the exact value of the expression sin45 + cos30

mellow kindle
#

Or use your calculator if your school allows you

dusky lark
#

how do I find cot (-pi/6) using reference angles

gray magnet
solar olive
#

cos(-x) = cos(x) and sin(-x) = -sin(x)

#

because cos is an even function

#

and sin is an odd function

tame flame
#

Hey! This may be the wrong chat but I don't know where to ask, I just got a new calculator and when trying it out I found that it says √2 = √2. How do I fix it?

solar olive
#

what kind of calculator? maybe u could send a pic

#

just press other number?

tame flame
#

Fixed it

solar olive
#

yeah u prob accidentally put sqrt(2) and pressed ok

#

🤷

#

my casio calc doesnt look like that tho so idk

tame flame
#

Yeah, unfortunately we didn't get to keep the school ones over summer

autumn wadi
#

so, how do I rigorously prove that:

  1. if I substitute a limit's value into the function I'm taking a limit of, if the numerator of the function is nonzero and the denominator is 0, then the limit doesn't exist
  2. If I did the same, but now both numerator and denominators are 0, then the limit may be exist
    ?
summer ruin
#

it seems like you want to prove something else than what you're saying there

#

"if i substitute a limit value... ...then the limit doesn't exist", but first part already assumes it exists?

autumn wadi
#

Ah right.

#

Hm...

#

How do I show that the limit won't exist unless I can factorise the numerator with a common multiple (which will show that it is a "removable discontinuity") tho? am I speaking sense here?

vapid plaza
#

Because you cant just “factor out” a zero from an arbitrary function

autumn wadi
#

Ah, true...

#

yes, I am

graceful heart
#

Hello, I want to learn Calculus Can anyone help me?

warped cipher
mellow kindle
pure pelican
#

Pls explain L'Hospital's rule with example .

lime bison
#

Ok guys so my friend is doing this double angle problem and I wanna know how the third solution isn't 7pi/6 (could possibly be 11pi/6) but why would quad 3 not be included?

graceful heart
graceful heart
viscid thistle
warped cipher
#

In this channel

lime bison
untold spindle
#

<@&268886789983436800>

lime oasis
#

anyone know any precal video for beginners??

lime oasis
#

?

turbid oxide
#

I am confused on part b. Here is my work and the solution from the back of the book

#

hm actually they say to express the real part

#

and jcos3t isnt real so my answer is correct

rich elbow
#

When given sin2(x-pi)

#

what is the horizontal shift of the function

#

is it pi to the right? or 2pi to the right

old kindle
#

how hard is precalc?

willow bear
#

depends on how adept you are w/ algebra, by a long shot

royal gust
#

Im so tired of mathematicians putting calculus in everything

#

Wait

#

This is pre calculus channel

#

What have I been doing if not calculus

gritty dirge
#

motion formulae are in that list

royal gust
#

I dislike calculus

gritty dirge
#

but please dont hate calculus. its a wonderfully useful tool with many real applications

royal gust
#

I always get integration and differentiation mixed up

gritty dirge
royal gust
#

Eh

#

I was talking about equations

#

Im only in year 1 of maths

gritty dirge
#

year 1 as in?

#

are you in grade 11?

gritty dirge
royal gust
#

No

#

As in year 1 of a level mathematics

#

I dont know how grades work

gritty dirge
#

a level

#

ok that is year 11

#

in total

#

a levels are a high school program of 2 years

royal gust
#

Year 12

#

Yeah

gritty dirge
#

then how are you a year 1 math student

#

im confused

royal gust
#

Year 1 of a level maths?

gritty dirge
#

anyways, calculus is a huge component of math in the a levels

royal gust
#

Oh

#

I thought it was only 2 modules

gritty dirge
#

you're gonna need to get comfortable with it

gritty dirge
royal gust
#

eeveeThink skip

gritty dirge
#

and you also have differential equations

lapis bramble
#

just leaned logarithms!!!!! calculus here I come

wanton matrix
#

yay

autumn wadi
#

whaddabout your trig sip

stiff nebula
#

What do you guys learn in precalculus?

uncut mulch
#

algebra, functions, polynomials
exponents, logs

shadow summit
#

Can someone help me with this problem? I know that A^2 creates an identity matrix but I can't figure out the second part, "find another matrix (not I) with the same property."

summer ruin
#

just use a number analogy

#

if (a)^2 = 1, then what else could be squared to output 1?

austere zodiac
shadow summit
summer ruin
#

the exercise doesn't ask for that

shadow summit
#

how else am i supposed to find another matrix with the same property then?

austere zodiac
summer ruin
#

if you can't think of anything then trial and error is another completely valid way

#

and it doesn't even have to be of the same dimension, the question just asks for a matrix with property A^2 = I

austere zodiac
shadow summit
summer ruin
#

no I think you're just overthinking it

shadow summit
summer ruin
#

a lot of basic LA exercises are really just trial and error and that's normal, it tests how well you understand the basic relationships and how well you can construct the desired result if needed

austere zodiac
summer ruin
#

(not necessarily -1 or 1, this is an abstract equation)

austere zodiac
shadow summit
#

when i was trying to find a general rule for the problem i was able to get it nearly correct but the diagonal numbers weren't 1

austere zodiac
#

This will be the property

summer ruin
#

general rule for matrices with this property is certainly not going to involve actual computation of A^2, it's deeper than that

#

and it's very likely to be far more than what's being asked

shadow summit
#

ok

austere zodiac
#

sorry if i dont helped you

shadow summit
#

its fine

austere zodiac
#

its hard to explain especially if I am not talking native language

shadow summit
austere zodiac
shadow summit
#

thought so, your username gave off spanish vibes

austere zodiac
short saddle
#

show me again

lucid trench
plucky oak
#

im struggling with precalc tests even though i can do the practice and hw, any advice

uncut mulch
#

take a few past papers under test conditions to try identify the cause

winter shuttle
#

how do i find real solutions to (4^x+2)(2-x)-6=0? (0,0.5 and 1 are easy to guess and they are the only solutions from the graph of it)

forest canopy
#

It's easier to guess them and then prove that they are the only ones, rather than trying to solve directly

#

f(x) = (4^x+2)(2-x)-6 is continuous, so you know when f(x) = 0 by checking where the sign changes (intermediate value theorem)

#

You already know that 0, 0.5 and 1 are such number, so you only need to know that it doesn't change sign before 0, between 0 and 0.5, between 0.5 and 1 and after 1

winter shuttle
#

yeah i was trying to do exactly that, to show there are no more solutions..but trying to show, say, that it is always negative between 0 and 0.5 seems difficult

forest canopy
#

You can look at the derivative of the function to know when the function is increasing or decreasing, it would then be easy to check what it's inferior to on some intervals

lament oyster
#

need help?

#

anyone

#

i am here

opal tree
white widget
#

Does anyone have a summary of infinite and trigonometric limits?

dusky lark
#

how do i find the coordinates i should use when graphing y=6sin(2/3x) -3

white widget
dusky lark
#

the period value?

#

and the amplitude/ vertical shift for the y axis?

white widget
leaden ocean
#

Can someone help me, how will I know. How much each point on the x-axis is when graphing transformations of sinusoid functions

stiff tapir
forest nacelle
#

can i please get help w log functions

#

we have to try and create a graph from locator points n the equation

#

is there a certain equation we use to do this

storm schooner
#

y=log(x)

dense mango
#

ok and

vital cairn
ripe meteor
#

Hello I need help with part b. I thought the answer was 19 but I got it wrong. Could someone look at my work for part b and tell me what I did wrong?

#

This is pre-calc compound interest formula. Nevermind I got the answer I just needed to add 19 to year 1995.

untold spindle
#

<@&268886789983436800>

gusty fulcrum
#

hallo

#

I need help with precalc

rigid flax
gusty fulcrum
#

how would I solve this?

willow bear
#

evaluate f(2) first

gusty fulcrum
#

how?

viscid thistle
#

💀

gusty fulcrum
#

someone actually help me please

#

would I start from that bottom point???

rigid flax
#

are there enough info?

gusty fulcrum
#

nvm I got it

#

i asked someone else, thx anyway

solar olive
# gusty fulcrum

evalute f(2)

from the graph, f(2) = -2

now do g(f(2))
= g(-2)
ffrom the graph, its 1

tardy glen
#

hello guys

#

i am trying to solve this

#

and i just discovered the u substitution

#

but i still can t figure it out

summer ruin
#

u substitution isn't going to help you here

tardy glen
#

oh

#

i am thinking to set up u=cos x

#

then i just have u^4

#

no ?

summer ruin
#

no

tardy glen
#

ok i think i have it

#

should i integrate by part since i have 0 in exponent ?

vapid plaza
#

The standard approach for even powers of sine or cosine is to keep using trig identities to reduce the exponent

#

Maybe consider using
2cos^2(x) = 1 + cos 2x

solar olive
#

cos(x)^4 = 3/8 + 1/2 cos(2x) + 1/8 cos(4x)

autumn wadi
#

Ah yes

#

Calculus in precalculus

solar olive
#

dont be too pedantic smh 🙄

autumn wadi
#

Either u use reduction formulae or product to sum

solar olive
#

alternatively, turn it into taylor series, integrate per term and leaev it as that

#

/s

shy vine
#

or just do the physicist approach by and say cosx = 1

#

(turns out its not a bad approximation)

tardy glen
#

ok guys the job is done thanks you

tardy glen
#

( i am maybe in the wrong channel sry i am new and i don t have acces to the calculus channel )

shy vine
#

I think you need the undergrad tag, idk specifically tho

tardy glen
shy vine
autumn wadi
#

I got pre uni

shy vine
#

I only have 1 role lmao opencry

autumn wadi
#

active

shy vine
#

I didn’t even choose that

#

It just gave it to me

polar tulip
#

does anyone know how to find the inverse?

solemn lantern
#

first u would do y=sqrt (x^2-1) then you would do x = sqrt (y^2-1) and then you would solve for y and that is ur inverse function

ripe meteor
#

When you do the inverse write y as f^-1(x) =

solemn lantern
#

yup at the end make sure you do that

ripe meteor
#

At the end

polar tulip
#

ok thank you!

#

what about the x>= 1

#

do we do anything with that?

solemn lantern
#

i think that just means the x values have to be equal or greater than 1 cuz if its like 0 which is less than then the square root wouldnt be a real number

polar tulip
#

does making the function inverse do anything to that though?

solemn lantern
#

im not too sure

#

maybe try graphing the inverse?

opal tree
#

f(x) fails the horizontal line test if the domain was R. The x>= 1 domain restriction makes sure that it suffices the horizontal line test and that f(x) is truly invertible

#

The range of f(x) will become the domain of f^-1 (x)

polar tulip
#

ohh ok got it thank you!

polar tulip
#

anyone know how this graph would look like? and how to find values of c?

willow bear
#

if yes:
are you able to graph y = x^2, y = 5.6-0.8x, and y=5 individually?

polar tulip
willow bear
#

well sketch the graph first

#

take the portion of y=x^2 that lies left of the line x=2

#

and the portion of y=5.6-0.8x that lies between 2 and 7

#

and the portion of y=5 that lies right of x=7

glossy carbon
#

correct.

hot roost
#
Khan Academy

The Precalculus course covers complex numbers; composite functions; trigonometric functions; vectors; matrices; conic sections; and probability and combinatorics. It also has two optional units on series and limits and continuity. Khan Academy's Precalculus course is built to deliver a comprehensive, illuminating, engaging, and Common Core align...

#

Would just doing this be enough for Calc AB?

thorn creek
#

it should be adequate prep for enrolling in calc AB

viscid thistle
#

Guys

#

a question

willow bear
#

rdj the question never came

thorn creek
#

it was lost in translation

summer ruin
#

<@&268886789983436800>

ripe meteor
#

If the focus is (0,-2) and the vertex is (0,0) then the equation of the parabola should be x^2 = -4ay, correct? Since the vertex is (0,0) and the focus is (0,-a) I thought it would have been x^2 = 8y because x^2 =-4(-2)y but it's marked incorrect by the program.

#

Any ideas?

stark shuttle
#

because the parabola is facing downwards

ripe meteor
#

Right!

#

Thank you!

stark shuttle
#

you're welcome 🙂

opal vault
#

wait why do u guys

#

multiply out the denominator

#

just keep it in the lhs

ruby sapphire
opal tree
thorny heart
#

Recently entered grade 10. i wanna know wether i should start studying this

#

how do i remove the he him tag? seems kinda cringe

uncut mulch
#

#Channels and roles at the very top

thorny heart
#

thx

gusty fulcrum
thorny heart
gusty fulcrum
untold spindle
#

<@&268886789983436800>

timber spindle
#

What exactly about geometry do i need to know or would i be fine if i skipped geometry and went straight into algebra 2?

ripe meteor
#

I'm currently taking pre-calculus in college. We are currently going over Conic sections. We already went over piecewise functions, complex zeros, properties of rational functions, polynomial and rational inequalities, exponential and logarithmic equations.

thorny heart
ripe meteor
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Nice! If you have any recommendations for resources then feel free to share because im self learning.

opal tree
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That's a thing?

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AP precalc 😭

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Ain't no way

thorn creek
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college board, always looking for a way to soak more money out of students

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someone is paying college board the fees for when you take an AP class

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if it's not you, it's your school district

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or whatever other entity funds your school

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my kids' high school pays the fees for AP students i think, but i'm not 100% on this tbh

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of course

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but the universal is that College Board expects to be paid

solemn lantern
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for me it was mostly a repeat of algebra 2 but a little bit harder and some more work

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shouldnt be too hard

solemn lantern
ripe meteor
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Me

timber spindle
opal vault
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geometry is triangles

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thats like 90 percent of it

opal tree
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What about them specifically

astral bronze
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A conic( cone shaped) are two intersecting cones using the formula for volume of a cone in 3 dimensions you can isolate specific slices

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It poses an interesting question like when an circle becomes an ellipse becomes a quadratic which is useful in hyperbolic trigonometry, relativity, and many others

opal vault
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conics

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so bad

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they are a bunch of memorization ngl atleast for me

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with the exception of parabolas and circles ig

ripe meteor
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I think conics are interesting. Let me talk about the ellipse.

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If the foci are near the vertices the ellipse is more of an oval shape however if the foci is closer to the center its more of a circular shape. Some ellipses are more oval than others. Planets orbits are an ellipse shape. The Eccentricity of an ellipse describes the ovalness or the roundness of an ellipse. It measures the ovalness.

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The sun is considered a foci

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The planet orbit with more eccentricity is mercury.

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If eccentricity is near zero then the ellipse is more circular but if its closer to 1 then its more oval.

ripe meteor
# opal vault conics

I don't think it's about memorization. It's more about understanding. Math is the language of the universe.

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There are vertical and horizontal ellipses each with their equation that is reversed.

thorn creek
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the sun isn't just "considered" a focus (foci is the plural, and so "a foci" is agrammatical), it is at one of the foci, that's a basic consequence of orbital mechanics

ripe meteor
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vertices is plural of vertex I get it

thorn creek
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actually the sun orbits the center of mass the same as the planet, but because the sun is wildlyl more massive its orbit is very tiny

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an eccentricity of 1 describes a parabolic orbit

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and greater than 1 a hyperbolic orbit

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some comets have orbits with eccentricity 1 or greater

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they will make one pass and then depart forever

ripe meteor
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Google- The eccentricity of an ellipse is always less than one. The closer the eccentricity is to zero, the more circular the ellipse. The closer the eccentricity is to one, the more elongated the ellipse. Eccentricity e= c/a

thorn creek
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yes, and an eccentricity of one describes a parabola

ripe meteor
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Oh I didn't know that I learn something new everyday

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Im now learning about conics

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Current unit

ripe meteor
ripe meteor
# thorn creek some comets have orbits with eccentricity 1 or greater

Are saying that some comets orbits hyperbolic meaning you only see it once and passes? That's pretty sad that people only get to see it once. Are there elliptical comets? I google search and it says that comets are highly elliptical. So, is the majority have elliptic orbits?

opal vault
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bro since

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when

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did this

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translate to keplers laws