#precalculus

1 messages · Page 23 of 1

gaunt sand
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facts

shadow summit
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methods ez, its just a bunch of basic calculus

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and probability ig

verbal rock
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hey i actually prefer living here than nsw i used to live in a crack house now i live in a mansion

shadow summit
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Dam, nice

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Dam even the crack houses cost a fortune

verbal rock
celest nexus
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<@&286206848099549185>

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no comprendo

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guys is it 12

spice steeple
celest nexus
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i just learned this

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like 2 secodns ago

spice steeple
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integral of f minus g is the same as integral of f minus integral of g

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man i wish i knew lateX

plush sparrow
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yeah

celest nexus
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what

plush sparrow
celest nexus
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what is goingon

supple wagon
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Basically, integral of (x+y) is the integral of x + integral of y

celest nexus
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ok

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that

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so is it just 18 - 6

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its

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its over guys

supple wagon
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No, the integral

spice steeple
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you need to evaluate the integral of -6 from -2 to 5

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also

plush sparrow
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do u know the constant law in integrals

celest nexus
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no

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i promise i learned this like

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actually

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a minute ago

plush sparrow
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integral of c dx = cx

supple wagon
celest nexus
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ok

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so

celest nexus
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😭

shadow summit
obsidian monolithBOT
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TheLord26

shadow summit
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so you would do: $ \newline \int^{5}{-2} f(x)dx + \int^{5}{-2}-6dx \newline 18+[-6x]^{5}_{-2} \newline 18-6(5)-6(-2)$

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latex?

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cmon

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work

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$\int^{5}{-2} f(x)dx + \int^{5}{-2}-6dx \newline 18+[-6x]^{5}_{-2} \newline 18-6(5)-6(-2)$

obsidian monolithBOT
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TheLord26

lavish crystal
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18-6(5-(-2))= 18-42=-24

lavish crystal
glad widget
ivory mango
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please do not ghost ping others

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well

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not ghost ping

glad widget
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Whats a ghost ping

ivory mango
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if you need help open up a help channel in the help forum

ivory mango
glad widget
ivory mango
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ghost ping = sending a message with the ping and then deleting the message

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cold ping is like pinging someone with an issue that the person they pinged has nothing to do with their problem

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also on a side note: "18-6(5-(-2))= 18-42=-24" is not precalc

glad widget
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18 - 6(5) - 6(-2)

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if i do what you did instead of straight up simplifying it i will pull out the -6 and get

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18 -6(5-2)

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= 18 - 6(3)

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= 18 - 18

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= 0

ivory mango
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that's not my point anyway

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it doesnt belong here as it's algebra

tender mist
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I was always confused on what is actually considered pre-calc, lol. I know the channel description says trig, logs, and exponents, but my precalc classes back then had like, everything including algebra

ivory mango
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yeah

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precalc is sort of a grey area

tender mist
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Yeahh, like I know it's normal for math to have a TON of overlap, but it feels like pre-calculus is the only early math subject that doesn't really have explicitly its own direction, it's just a combination of things

ivory mango
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like right now I was given a notes packet in class and it had "what is e" and "what is a natural log"

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and I was the only person in class to not only know the value but what e represents

river drift
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the weird stuff is when pre-calc classes cover limits, because for me limits are definitionally a calculus topic

tender mist
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Yeahh, that definitely stumps me as well. Not even just definitionally, but historically limits were conceived with derivatives

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so it's a bit odd for sure

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Or at least, limits as we know them. Limits were technically informally used in the Greek era, but not the way we use them, and it definitely wasn't a well-researched topic at the time

shrewd flicker
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Heyy! Is anyone interested in reviewing pre-calc with me for the next 2 weeks? We can be study buddies 😎 I completed pre-calc during my first semester of college and want to make sure that I review the units before starting Calculus.

shadow summit
shadow summit
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i mean, its more like calc than precalc, but eh

glad widget
ivory mango
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Where

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All I read was that algebra

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Oh

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It's right above it

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I didn't see it at first

barren finch
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Hey guys, a quick question. I have already done pre-calculus and even tho I am moving to calculus. I don't feel confident moving toward calculus, so can you provide me with some suggestions? Thanks.

ivory mango
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Do some practice problems

fleet sinew
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Hi and what?

tepid timber
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Why not just leave

uncut mulch
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<@&268886789983436800>

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(check logs too)

analog flower
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@pure oak ^

swift stone
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The Stewart's book for PreCalculus has been pretty decent so far

willow bear
analog flower
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i think it was the logs from them

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but they got banned i think

willow bear
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something something "logs" pun

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banned for logs in the precalc channel [vine boom x4]

uncut mulch
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they were asking to get banned and also try see what happens when you look up messages from them

fast kiln
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Can anyone explain how, after finding the length of PQ, to do next part ii)

willow bear
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this pic is very low res

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take a better one

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The diagram shows part of the curve y = x(9-x^2) and the line y = 5x, intersecting at the origin O and the point R. Point P lies on the line y = 5x between O and R and the coordinate of P is t. Point Q lies on the curve and PQ is parallel to the y-axis.

(i) Express the length of PQ in terms of t, simplifying your answer.

(ii) Given that t can vary, find the maximum value of the length of PQ.
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ok i transcribed it

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@fast kiln do you know how to find the max value of a function in general

fast kiln
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Setting the derivate equal to 0

willow bear
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well, why don't you do it here?

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you've got PQ as a function of t.

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maybe before that, it would be nice to find the range in which t can vary. so that you're clear on the domain.

kindred basin
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i just started exponential functions and logarithms today

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its neat

fast kiln
# willow bear you've got PQ as a function of t.

Okay but I’m still a little confused on how it works. Isn’t dy/dx a gradient function? Like for a curve I get how you can find the max or min points but how does it work for a vertical line?

willow bear
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you're overthinking it right now

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you should just view 4t - t^3 as a function of t REGARDLESS of where it came from

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you have this function and you need to maximize it on the domain 0 ≤ t ≤ 2, that's it.

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abstract away from the details, so that they do not cause such confusion.

fast kiln
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Okay yeah but now I’m curious. Does this change anything about dy/dx being a gradient function and that by setting the derivate of a curve equal to 0, you are simply finding a horizontal part of the curve?

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i still dont really get it (i can answer the question now but dont get why/how)

viscid thistle
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Hello, I'm just new here can someone please help me with my math 🥲

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Legit just joined here cause I've been stuck with this math for 2 hours and I haven't made any progress 🙃

tender questBOT
willow bear
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we need to see it in order to help you don't we

viscid thistle
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Mb

glad widget
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how can i figure out where these 2 equation intersect?

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setting them equal gives a linear equation

glad widget
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nvm i figured it out

viscid thistle
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hello anyone

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im new to these kind of stuff uhh

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can i ask

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f:x→2x+1
f(x)=2x+1
y=2x+1

are these 3 the same value ?

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please ping me because i rarely check servers😭

worldly marsh
viscid thistle
river drift
viscid thistle
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hi, terrible high school, learn almost nothing. Recently bought Axler's pre calc book and im loving it. Do you think someone can learn the entirety of pre calc plus the entirety of calc 1 and 2 in 4 years while studying for 1 hour a day?

summer ruin
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it's not efficient to study 1 hour a day math subjects

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you can learn all of this in under a year

vapid plaza
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you can learn all of calc 1 and calc 2 in a day if you're really smart

shadow summit
grim maple
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if delta = 0 , its represents pair of straight line

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if you wanna find the angle between them, you can use tan(theta) = (2(h^2-ab)^1/2)/a+b

swift stone
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is there a free version of wolfram floating around

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something that shows you the result and how it got to it

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?

swift stone
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first off make sure you're stuyding for the 1 hour like no outside distractions nothing just you and the work

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second thing I would say if you can try and increase the time as you go along

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a little focused studying is better than none / hours of unfocused studying

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also if we're giving advice could we like actually add something of use besides saying nah that's kinda dumb

old pollen
old pollen
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Way to much stuff

hollow crypt
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im stuck on how to do this

old pollen
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Hi rocinate

viscid thistle
old pollen
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Cause it’s like constant

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T-10 obviously but idk

viscid thistle
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well just off the top of my head, it looks like it covers 180 degrees during 10 minutes (for times less than 10 minutes)

old pollen
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I think either cos or sin is good?

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Idk though

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Oh it’s like geometry sort of?

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Oh it’s geometry

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Ha ha

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Unit circle moment

viscid thistle
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So in 1 minute it should rotate a 1/10th of that. so 18 degrees? maybe

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yeah

old pollen
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If 10 mins=1 dial I could solve it

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Idk though

hollow crypt
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doesnt it look like

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a lil more than 180

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for 10

viscid thistle
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yeah maybe, what can we do about it, lol?

hollow crypt
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soooo whats the asnwr

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for 1 i think its

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like

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20 degrees right

viscid thistle
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maybe 18 ish

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lol right kind of an estimate

hollow crypt
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ok yeah

viscid thistle
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yeah maybe 19 or 20

old pollen
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280 degrees from 0 to 35 mins I think

hollow crypt
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wait what

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wouldnt it be the same

old pollen
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One circle is equal to 360 degrees

hollow crypt
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itll be even less tho right

old pollen
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🤓

hollow crypt
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cuz now the interval is 5

viscid thistle
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i think you will need to the any of the ones that involve the "upper" part of the time in pieces

hollow crypt
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and 1 minute

viscid thistle
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like split into 2 different problems

old pollen
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I’m not helping I’ll leave

hollow crypt
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it would be less than the first answer right

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like 5 degrees

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cuz its asking in 1 min

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so

viscid thistle
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oh so problem 2... it has a constant rate still (but the other constant rate)... ok let me try

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so what do you think, from 35 to 11 minutes on the dial is about 90 degrees?

hollow crypt
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uh

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what does that mean

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theres no 11

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oh

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wait

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like about yeah

viscid thistle
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I got 3.6 degress for teh 2nd problem

hollow crypt
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ok thanks

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wwait thats what the question is asking right

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like

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its asking to scale it down

viscid thistle
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it wants to know how many degrees the knob will turn during a certain time period?

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well part 3... is kind of like slope.... we divided the change in one quantity by the change in the other

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for the first problem: (180 - 0)degrees/(10 - 0)minutes = 18 degrees/minute

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in the second one: (90 - 0)degrees /(35 - 10)minutes = 3.6 degrees/minutes

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Δy/Δx same idea

hollow crypt
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ok thanks

surreal yoke
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anyone got great videos that help you learn linear and quadratic systems (grade 11 Alberta curriculum) to make it easier to understand?

hard verge
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our school follows indian system, so we got high level stuff

spiral sonnet
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What did I do wrong? Given 1/x+6 and the interval [7, 7+h] I was asked to find the rate of change so I plugged them in y1 = 1/13, y2 = 1/h+13 and then did y2-y1 / x2-x1 and ended with h^2 / 13(h+13)

viscid thistle
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, ask (1/(h+13) - (1/13))/(7 + h - 7)

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, ask simplify{(1/(h+13) - (1/13))/(7 + h - 7)}

obsidian monolithBOT
viscid thistle
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not sure where you got h^2 in your numerator; but I'm kind of rusty, heh

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double check it maybe

spiral sonnet
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Uhhh well…. I musta done something either on accident or I just have no idea what I was doing lol

whole spruce
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is (2x-1, -6y+4) the right mapping notation for this functions?

gentle tartan
lean tundra
# gentle tartan

this is really not complicated I would advise you to read more carefully the question

shadow summit
obsidian monolithBOT
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TheLord26

lethal patrol
shadow summit
lethal patrol
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I figured it out already

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Thanks for answering though

arctic sundial
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How do I do this

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I’ve tried foiling and factoring but I haven’t gotten anywhere

shadow summit
arctic sundial
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But I wanna try without substituting

uncut mulch
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numerator would need to evaluate to 0 when x=k

arctic sundial
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Don’t you need to factor so the numerator is the denominator

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Oh

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Wait

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I’m still cpnfused

uncut mulch
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factor theorem

arctic sundial
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I found the answer key but I don’t understand

uncut mulch
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if (x-k) is a factor of the numerator,
the numerator will be 0 when x=k

arctic sundial
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When x = k its a hole and undefined, no?

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You have to factor it before you can find y value of the hole

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Oh wait

arctic sundial
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So what does that mean

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I can create whatever binomial I want?

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I’m still confused sorry

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I substituted k for x

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And x is 3 which means k is 3

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But idk how that works still

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But then that gives me this

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Which is undefined

uncut mulch
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replace x with k

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for the numerator

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then solve for when the numerator will be 0

solemn moss
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Does anyone know where I can learn calculus for free cos I can’t afford university and I can’t take calculus at my school

solemn moss
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Thank you🙏

spiral sonnet
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I’m confused about reflecting the y/x axis when it’s something like 5^x

I thought reflecting the x axis meant flipping it horizontally so -1 would equal 1, etc. but apparently doing -5^x is reflecting the x axis?

summer ruin
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reflecting along x axis

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but yes

novel sigil
lean jasper
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How do you graph piecewise function?

shadow summit
lean jasper
shadow summit
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Npnp

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You just graph the functions but cut it off where each of the domains are

lean jasper
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Okay but where are the domains?

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I'm quite new

shadow summit
lean jasper
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Okay

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And

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Probably the last question: when do you need to pluck the number in a domain into f(x) = mx + b ?

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I am quite confused at this point

lunar flame
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Can you guys please share some topic exam questions to practice for Edexcel Further Pure Maths IGCSE: Sequences and Series, Vectors, Binomial Expansion and series, Quadratics, Coordinate Geometry, Exponents and Logarithms, Inequalities and Identities, Sketching Polynomials

strong epoch
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Does anyone know what I got wrong on these

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?

dense cobalt
lean jasper
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Anyway thanks @shadow summit

last pine
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How do you do 64.

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Im lost rn

mystic basalt
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i think change cosx into sin(90 - x)

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then apply formula sina + sinb

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u get smthin like this
2sinxsiny = 0, from there you can make a general solution

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in the next one put sec^2x = tan^2x + 1

slim crystal
#

alr

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so how do u even start this problem

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ik sec is inverse of cosine

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but how do i find secant of pi over 5

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without a calculator btw

summer ruin
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you're not supposed to

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use properties of cosine and trig circle

slim crystal
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what

marble leaf
# slim crystal

u can use the period of sec and the fact that it’s an even function

exotic sky
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wait why do they all look equivalent

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wait nvm

stable vessel
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Are all of the properties here true?

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Yes they are

viscid thistle
#

x
1⁄2
= 6

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i need help

pure copper
lime lotus
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Am I saying this statement right?

A ↔ B

"A corresponds to B"

lime lotus
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Like ∠A ↔ ∠B

"Angle A corresponds to Angle B"

random yoke
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what do you mean by correspond

lime lotus
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correspondence

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A is to B

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like that

random yoke
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the angles are equal in measure?

lime lotus
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yes like that

summer ruin
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and this is not how mathematicians would read it

lime lotus
vapid plaza
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"correspond" is not a mathematically conventional word afaik

lime lotus
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What is the correct way?

summer ruin
#

there is not a single correct way

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a mathematician would read it as A if and only if B

lime lotus
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So let's say I saw it on a beginner geometry book

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How do i read it?

summer ruin
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depends on the context

lime lotus
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Let's say about on congruent angles

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How

summer ruin
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can you post the entire context?

lime lotus
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like a one-to-one correspondence of vertices of two triangles

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wait I'll take the picture

lime lotus
summer ruin
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read it how your book reads it, a correspondence

lime lotus
#

a correspondence b

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like that?

summer ruin
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a corresponds to b

lime lotus
whole void
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I don’t think explaining it as a bijection is a great way to put it

willow bear
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do you have something better in mind then @whole void

whole void
#

but yeah for triangles it makes more sense

willow bear
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well this is in the context of triangles

whole void
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yeah sorry i misread i thought it was talking about just two angles

gentle sapphire
#

Guys do you think that the precalculus book by james stewart takes a good approach on trigonometry because i dont think so, its very short and doesnt explain anything in detail, is there a reason for that? Should i go with an alternative?

shut current
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i have a composite functions test and Rates of Change test on the same day and i cant find a good review sheet. does anyone here have one?

abstract quarry
#

Guyss suggest any good self study (with a good explanation) for precalculus

abstract quarry
#

Plzz anyone

uncut mulch
#

khan can give you a decent intro

abstract quarry
#

did u mean khan academy

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if yes then I'll definitely try, I'm learning from this channel called "Bhannat Maths"

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But finding it difficult to solve questions on relations

gentle sapphire
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Guys, when it comes to the unit circle in the unit circle, i dont understand how the points in p calculated, like where did we get square root of three over two and 1/2? Is it somethin specific to that triangle or how can these numbers be calculated?

willow bear
#

Is it somethin specific to that triangle
yes
how can these numbers be calculated?
by viewing the 30-60-90 triangle as half of an equilateral

abstract quarry
#

Guyss suggest any good self study (with a good explanation) for precalculus

gentle sapphire
shadow summit
patent tundra
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please help how can i solve part a of this?

summer ruin
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"is a solution" means when you plug it in the equation, it turns true

jolly dew
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Hello! I need some help. How would I find the zeroes of trig functions without a graphing calculator?

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ex.f(x)= 1/2 (cos2x)

jolly dew
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Okay I know the trig circle but how?

summer ruin
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see where on the trig circle the cosine turns to zero

jolly dew
#

Okay but in that case,
1/2 cos2x=0
cos2x=0
and then what should I do?

summer ruin
#

do you see for what inputs the cosine turns to zero on the trig circle?

jolly dew
#

1 or -1

summer ruin
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there are no such points on the unit circle

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remember that the horizontal axis is for cos(x) and vertical axis is for sin(x)

crisp bluff
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log(a)/log(b)=a/b

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is that a rule?

fading monolith
#

No(?

crisp bluff
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ok

river drift
#

,,\frac{\log (a)}{\log (b)} = \log_b(a)

obsidian monolithBOT
fading monolith
#

That yes

viscid thistle
#

i need some advice regarding studying calculus, before accessing topics like derivatives and integrals, what are the topics i need to study?

summer ruin
#

trig, algebra, learn all the basic functions and their properties

viscid thistle
#

im studying applied maths

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( no trig )

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does the chapter Relations relate to it?

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like calculus

summer ruin
#

if you don't have solid foundation in trig you're going to suffer a lot in calculus

viscid thistle
#

alright, thanks a lot

viscid thistle
summer ruin
#

well how could I know that based off of chapters name

mossy hound
#

i learned the hard way that when i found out that trig is important for some limits

rough jasper
#

Hello I am having trouble with Models and Applications. Can anyone recommend any resources to help me understand the topic better. I am having a problem with verbal expressions in word problems and having to turn it into mathmatical expressions.

rancid forum
#

Why isn't the answer no roots? I got x=-17, but when i plugged x back into 0=... get 8=0. I asked wolfram alpha and it said there's no roots..

river drift
#

if you plug in x = -17 it should give you 0. i think you must have made a mistake when plugging in

delicate oriole
#

someone good with complex numbers?

rancid forum
#

thx

tender questBOT
delicate oriole
solar olive
tropic obsidian
#

is there anyone that wants to vc and work through math problems? im on exponential and logarithmic functions and kind of have nobody to talk to in my class to sort them through

rain scroll
#

Sorry i am to sleep

tropic obsidian
#

all good!!

lean tundra
# tropic obsidian is there anyone that wants to vc and work through math problems? im on exponenti...

the logarithm function is the reciprocal function of the exponential which means that if $ln(x)=y$, $e^y=x$, For example $ln(1)=0$, and $e^0=1$
It's a function that is defined in $\mathbb{R}+$
$\lim
{x\rightarrow 0} ln(x)=+\infty$ and $\lim_{x\rightarrow +\infty} ln(x)=+\infty$
The derivative of the function is $\frac{1}{x}$
This is the basic of the function ln but I would do reseaches on google because the function has quite a lot of properties TBH and to understand some of the demonstrations for the derivative etc.

obsidian monolithBOT
willow bear
thin dome
#

prove continuity of the function $\cos x$

obsidian monolithBOT
glass dove
#

what am i doing wrong here?

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the differential quotient should be 2

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since it goes up 2 points

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someone please help

willow bear
#

it goes up 2 but also right 2

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so you are not doing anything wrong @glass dove

lean tundra
willow bear
#

and what you call inverse we call reciprocal

lean tundra
rancid bluff
#

What exactly is euler's number and how does it relate to logarithm?

I don't really understand. Cause like the log2 8=3 makes sense. But I have no idea what e does or why its even a thing

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I hope I explained that well. English is not ny first language

river drift
#

euler's number e is a number with a lot of special properties that makes it show up a lot in calculus. the functions e^x and ln (natural logarithm, log_e) have very nice properties when it comes to calculus. So they show up very naturally in calculus courses. unfortunately i don't think there's much justification to give other than "you'll need it for your calculus course"

rancid bluff
#

Oh I see. Thank you so much for answering my question :))

spiral sonnet
#

To find the regression equation on desmos I input the data then on a separate line do y1 ~ mx1 + b
and then I use the M and B to make my equation right?

river drift
#

if it's a linear regression then yes

spiral sonnet
#

Thats what I thought but it never seems to satisfy the question

river drift
#

what do you mean by that?

spiral sonnet
#

I am asked to find the regression equation to the accurate 2 decimal place using desmos as part of some exercises

This is what I was told to input to find it but when I respond with y = 1.77x - 75.09 it doesn't satisfy the question

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Am I doing something wrong?

river drift
#

you didn't round them correctly

spiral sonnet
#

So this is asking me to round it? I figured accurate to two decimals just meant what it is

river drift
#

"accurate to two decimals" means round to two decimals. 1.78 is closer to 1.77915 than 1.77, so it's more accurate

spiral sonnet
#

I hate math in english. That was my problem, thank you

river drift
#

in general if a problem asks for a certain number of decimals, you should always round it

spiral sonnet
#

Somehow I never knew that, thanks for the clarity.

lean tundra
#

no jk

river drift
#

that's what the calculator is doing anyway

viscid thistle
# spiral sonnet Somehow I never knew that, thanks for the clarity.

also because if it is a computer grading you, well they aren't very smart so if it asks what pi and tells you to type in 2 digits after the decimal, and you put in 3.1416 it is prob going to test to see if 3.14 = 3.1415 and when it finds that it doesn't match, it will probably decide the answer was wrong.

#

,ask 3.14=3.1416

obsidian monolithBOT
viscid thistle
#

that is what it is prob gonna do

#

cuz it is a computer

#

computer grading has to be hell... I feel so bad for you guys (I'm kind of old so I didn't have to deal with this crap).

alpine anvil
#

can someone help me pass this test

#

like hop on call and explain the entire test to me

#

<@&286206848099549185>

coral pewter
#

how do i convert a cartesian equation to a rectangular one i kinda forgot

river drift
#

is that not the same thing?

toxic jetty
#

Chat, I got a precalc exam tmrw, any tips for it?

honest aurora
#

Breathe air

#

Smile

uncut jay
#

ARE THESE CORRECT?!??!?!?!??!!

#

its my last attempt and ive been getting these wrong

willow bear
#

you in a test or what?

uncut jay
#

worksheet

willow bear
#

how come you have a limited number of attempts

uncut jay
#

ask my professot

willow bear
#

Q5 appears correct but for Q6 it doesn't say to round so you might want to go for an exact fraction in terms of pi

uncut jay
#

is automatically rounded to that

#

Im scared to press submit

velvet iris
#

it's not incorrect but the automatic grading might fault you for rounding

uncut jay
#

yep I god faulted

#

got*

#

never understood them, fuck this shit

idle goblet
#

Don't know what I did wrong here the answer is -4÷3 but I get -8÷3

rough minnow
willow bear
#

missing dx?

rough minnow
#

Oops

willow bear
tender questBOT
rough minnow
#

Hmm i solved it but idk if it's the correct answer

#

Ok is this correct please tell me

#

I've solved it but idk if this is correct please verify if any mistakes

rough minnow
silk needle
#

quick question

#

what is this type of function called?

half solar
#

That looks like a rational function

shrewd bronze
#

If something is differentiable it’s continuous, but something continuous is not necessarily differentiable

silk needle
#

idk

silk needle
river drift
#

the general class would be an algebraic function, which also includes polynomials and rational functions

silk needle
#

its just im unfamiliar with the name of the function itself

river drift
#

note that your graph was entered onto desmos wrong

#

not every function necessarily has a special category it fits into

silk needle
#

i understand

idle goblet
#

How can I write any quadratic equation as the multiplication of two expressions?
For example 2sin^2(x) + sin(x) - 1

fading monolith
brazen valley
#

I was doing this integral (integral of cos^3xsinx) the other day, and found something peculiar which I would love for someone to explain to me. Using the substitution ‘u = cosx ‘ the answer I got was -1/4 * cos^4x + C, and using the substitution and some repeated use of the Pythagorean identity I got the answer ‘1/2 - 1/4 * cos^4x + C’

#

These are both equivalent given the 1/2 can be absorbed into the constant

#

But I was wondering where exactly the 1/2 came from

#

I asked my marhs teacher and he said probably the u sub due to a different transformation being carried out, but he couldn’t explain exactly why

#

Could someone please explain where exactly the 1/2 comes from

#

I was thinking the pi/2 phase shift between cos(x) and sin(x) has something to do with it but I don’t know exactly

brazen valley
#

the sqrt(3x^2) basically means sqrt(3)|x|

#

if u swap that out for sqrt3 x u would get a hyperbola I think

#

some transformation of y = 1/x

lean tundra
#

should be like this tho

silk needle
fading monolith
brazen valley
#

Sry i lost it i had to rewrite

#

but I got 1/4 this time

#

Might have made a mistake before

#

Or now

#

But it’s the same thing

#

Where did it come from

#

And y did the u sub do thay

#

that

#

1/4 is 1/4 of their periods maybe smth to do with that

brazen valley
fading monolith
#

Mmmm well I wont care to much about that 1/4, thr integral is a family a functions that differs one constant so

brazen valley
#

Yeah Ik

#

that’s what i keep getting told

#

But I just wanna know y the u substitute brings that 1/2 into the equation

#

It’s a neat number so there must be some good reasoning

#

related to the substation being a transformation

#

the actual integral doesn’t matter it’s just interested in what’s happening when you do different substitutions

willow bear
fading monolith
#

Since your sustitution is with sin and not cos, and is cos^3 whats bothering you

brazen valley
#

The only difference is the u sub

fading monolith
#

I know

#

But did more algebraic manipulation for the second substitution. Again, dont worry about that 1/4

#

Appears because of getting different substitution and thats it

#

Notice that arcsin(u)=x and cos(arcsin(u))=sqrt(1-u^2) so if you susbtitute from the begining you will get u(1-u^2)=u-u^3 so its inevitable to get that 1/4

spiral sonnet
#

Given the points (2003, 1483) and (2007, 2239) I use point-slope formula to get the equation y=189x-377084

with this i manage to get every single question I am asked correct (by an automated grader)
but when they ask for the equation for some reason this doesn't satisfy it?

willow bear
#

are you 110% sure that there's no arithmetic fuckup in your work

#

also show a screenshot of the problem as it appears on your device

spiral sonnet
#

Yes because they ask me to give specific Y's using my equation and I satisfy all the given x's

willow bear
#

so we know there is no input error or anything

#

,calc 189*2003-377084

obsidian monolithBOT
#

Result:

1483
spiral sonnet
willow bear
#

,calc 189*2007-377084

obsidian monolithBOT
#

Result:

2239
willow bear
#

t years after 2000

#

t isn't the year itself

#

it's the number of years since 2000

#

so you would be using the points (3, 1483) and (7, 2239)

spiral sonnet
#

ooooh

willow bear
#

this is why the !original factoid exists lmao

spiral sonnet
#

idk what that is but now it makes sense lol

#

thank you

willow bear
#

!original

tender questBOT
#

Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.

willow bear
#

we have a factoid for this exact situation

spiral sonnet
#

wait actually this doesn't solve my problem, because when I calculate for M it's still pretty much 7-3

#

Or am I just being stupid

willow bear
#

it's not m that is the issue.

#

the slope is ok

#

it's the y int that isn't

spiral sonnet
#

oh right

#

when I do point slope I don't do 2000's

#

nvm

lapis bramble
#

I'm actually so confused like I know the trig identidys and stuff but how in the world do I do this with no calculater

summer ruin
#

arccos(-0.65) = x -> cos(x) = -0.65

#

recall what is the range of arccos - that would be the domain of cosine in the equation cos(x) = -0.65

#

then recall the trig circle and see where you get the cosine to be approximately -0.65

lapis bramble
#

one ces lemme draw out what I'm getting from this

#

sec

#

so like this and because 2.28 is closest that whould be right?

summer ruin
#

I don't get what you're trying to say

lapis bramble
#

whoops not -6.5 -0.65

summer ruin
#

try to answer the question on what x is in the equation cos(x) = -0.65 instead of trying to measure arclength

lapis bramble
#

isnt the arc length the same as x?

#

cuz thats what cosine is

summer ruin
#

sure, but that only complicates the question

#

you should know at what x you get cos(x) = -1/2

lapis bramble
#

yeah I do but I only remember when I draw out the unit circle so thats why I did 3pi/4

summer ruin
#

well you won't be able to answer the question with that information because you don't know what cos(3pi/4) evaluates to approximately

#

-sqrt(2)/2 is some difficult to estimate number

lapis bramble
#

so I just think what cos do I need to get aprox -0.65?

#

so I can do -0.5

summer ruin
#

what x do you need such that cos(x) = -0.65

lapis bramble
#

yeah I get that but like how do I figure that out (also thx so much for helping me with this)

summer ruin
#

just give me a range of values of x such that you can ensure that cos(x) achieves value -0.65 in that range

lapis bramble
#

0-pi?

#

pi/2-pi

#

not 2-pi

#

pi/2 throu pi

summer ruin
#

I mean the question is setup in such a way that just saying x belongs to 0 to pi already makes the answer obvious

summer ruin
lapis bramble
#

3pi/4 right

summer ruin
#

no

#

cos(3pi/4) = -sqrt(2) / 2

lapis bramble
#

oh yeah

#

i know this one sec lemme get a paper

#

sqrt(3)/2!?

summer ruin
#

well why suddenly it wouldn't contain any pi? such a value is certainly not on the trig circle

lapis bramble
#

oh yeah duh thats the y-cord

#

pi/3

summer ruin
#

cos(pi/3) = 1/2, not -1/2

lapis bramble
#

or 4pi/6 I mean

summer ruin
#

yes that's the same thing as 2pi/3

#

well then you know that 2pi/3 < x < pi

#

this answers the question

lapis bramble
#

yes

#

so then whats the answer

#

like ig 5pi/6 for an aprox and the clossest to that wins

summer ruin
#

and conclude the answer from that

lapis bramble
#

so its 3.28?

summer ruin
#

what is

#

there's no such answer option

lapis bramble
#

2.28 whoops

summer ruin
#

yes

lapis bramble
#

ok I understand it now thank you

rugged ferry
#

could anyone solve these

willow bear
tender questBOT
rugged ferry
willow bear
#

write out both planes' trajectories as parametric equations in 3D space tbh

#

like, run the x-axis parallel to one of the planes' courses, the y-axis hoizontally perpendicular to that, and the z-axis upward

#

also be careful with units (feet for distance vs. mph for speed... one of these gotta get converted at least)

twilit echo
#

can anyone tell me how to solve this?

river drift
#

try substituting the part under the square root

#

in general integration questions should go in #calculus

shadow summit
obsidian monolithBOT
#

TheLord26

shadow summit
#

Now apply the reverse chain rule or use u-substitution

willow bear
#

what are integrals doing in heree

shadow summit
dense hound
#

Pre Uni roles don't have access to calculus

fading monolith
#

But the guy have an undergraduate role

atomic haven
#

@twilit echo

willow bear
tender questBOT
# atomic haven -8/3 . ( 1-x^2)^3/2

As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.

atomic haven
atomic haven
uncut mulch
#

answers, solutions, same thing
the point is don't give them away like that

spiral sonnet
#

Would have had a 100% on my exam if I didn't accidently give all decimal points instead of reading "to the nearest one decimal" 😦

shadow summit
# viscid thistle to me you got 100% 🙏

No, that is a valid reason for not getting 100%. It’s harsh but it was also stated in the question. Besides, if you “give all decimals”, especially in a non-calculator exam, you are probably wrong. The standard is rounding to 2 decimal places.

viscid thistle
uncut mulch
#

rounding of stated is part of the question after getting a more precise answer

#

you're essentially missing a step which is cause for deducting marks

#

much more important if it's stuff related to significant figures

spiral sonnet
#

There were only 4 decimals but I do agree it was my fault.
Sucks though lol

shadow summit
onyx lotus
#

hi what is the formula they are using to solve?

river drift
#

that's the formula for the slope of a secant line to the function passing through the specified points

#

it's a special case of the general formula for the slope of a line passing through two points

naive tundra
#

Need help

silver dove
#

@naive tundra Let's put the second one in the form y = -x-1

#

and let's make them equal to each other and find the points where they intersect

#

Then apply integral

naive tundra
naive tundra
silver dove
#

Now we need to find which function is higher than the other in this range

#

Finding the focus point of the quadratic function may be useful

#

-x²+x+2

#

We need to replace -b/2a

#

b = 1
a = -1

#

-1/-2 = 1/2

#

when x = 1/2

#

the function is at its maximum point

#

well let's try

#

-(1/2)²+1/2+2 = -1/4+1/2+2

#

= 2.25

#

as you can see

#

They intersected at (-1,0)

#

first

#

If we start from the left

#

Well, then we know that the polynomial must increase to reach the value 2.25

#

but they never intersected again until x = 3

#

So between -1 and 3 the polynomial was larger than the linear function

#

After 3 the polynomial is smaller

#

because it reached its focus point at 1/2 and will decrease because the a is negative

#

ax²+bx+c

#

This is what is meant by "a"

#

Now we will subtract the lower function from the higher function in the range -1,3

#

like -x²+x+2-(-x-1)

#

= -x²+2x+3

#

and we will integrate this in the range -1,3

#

dx of course

#

So this means, first integrate the polynomial in the range -1,3

#

you will find an area

#

but it will be incomplete

#

Then you will integrate the linear function between -1 and 3

#

and you will get an area too

#

but you have to subtract it from the first integral

#

because it is higher and if you subtract the lower from higher you get a positive value

#

So think of it as if line segments were drawn between them in the range -1,3

#

and when you add the lengths of these line segments in the given range, you get the area

#

The lengths of the line segments are f(x)-g(x) for each x value

#

where f(x) = -x²+x+2

#

and g(x) = -x-1

#

If we were asked to do it in the range -1 to 4, first we would subtract the linear function from the polynomial again since the polynomial is larger in the range -1 to 3.

#

But since the linear function is larger than the polynomial in the range 3.4, we subtract the linear function from the polynomial

#

and we take the integral in the range 3,4

#

and then we would add these two values

#

Area in range -1,3 and area in range 3,4

#

It's like dividing a square in half and such as finding the areas of the two rectangles formed by dividing the square in half and adding them together

#

again you get the area of ​​the square

naive tundra
# silver dove like -x²+x+2-(-x-1)

I have a question, why the integration of -x^2+x+2 - (-x-1) have to substract integral -x-1 again? Isn't we have already the area between the line and the curve?

silver dove
silver dove
#

because there are overlapping areas

#

if you noticed

#

If you can find a video about this, maybe you will understand it better

#

area limited by two functions

shadow summit
#

In future have these discussions in the appropriate channels.

dusky moon
#

Hey

#

I need help with a math homework

#

but is in spanish

#

can someone help pls?

karmic igloo
#

where are you blocked?

shadow summit
# dusky moon

For question 1 you have to cube equation 3. You can do this by just expanding or using the binomial expansion.

#

For question 2 set make equations 1 and 2 equal, and then solve for x.

#

For question 3, multiply the top and bottom by the conjugate (1+i). Seperate the fraction, then you can find the real part.

dusky moon
#

yo thanks

shadow summit
# dusky moon yo thanks

Do you think you can solve all of the questions with this info? Or do you need me to explain how to do the other ones

dusky moon
#

i think i'm ok

#

a) is -8

#

i think

#

@shadow summit Where are you from, or how did you learn to speak Spanish?

#

normally on this type of servers nobody speaks other languajes than english

shadow summit
#

I mean, most of the key words are pretty similar, so understanding what they wanted was kinda easy.

dusky moon
#

yo your'e a god guesser and also good at math

sour glade
shadow summit
#

Skill.

sour glade
shadow summit
#

Type “,,” or put latex code in $between solar signs$

obsidian monolithBOT
#

TheLord26

shadow summit
#

I’m not teaching you latex.

sour glade
#

,, \int_{0}^{\frac{1}{e}}\left(\frac{\cos\left(x\right)\sin\left(x\right)^{x}}{\pi x^{\tan\left(x\right)}}-\frac{\int_{0}^{e}\left(x^{a}-60^{a}+9\right)da+\tan\left(x\right)^{\pi x}-68x^{\sin\left(x\right)}e^{e^{x}}+\ln\left(x^{x}\right)}{\int_{0}^{\pi}\left(a^{x}-x^{60}+9\right)da+\tan\left(x\right)-\sec\left(x\right)+68\sin\left(x\right)^{x}e^{x^{e}}+e^{x^{x}}}\right)dx

obsidian monolithBOT
#

Vanouper

sour glade
#

Lol, this equation is so large that it can't even fit it all in.

shadow summit
woven ravine
#

how the heck does it just become 1/sinx-sinx to 1- sin^2x/sinx?

solar olive
#

do u not know how to combine a fraction

woven ravine
#

wait nah i got it

#

had a brain fart 💀

lament glacier
willow bear
#

also be careful with the word "inverse"

lament glacier
#

Yes I know, the inverse of sin is actually arcsin

#

Sorry for my bad english

#

Sorry, My bad 😑, how did I explain it? 😪

lean tundra
dusky moon
#

hi

#

Can someone help?

#

I need to find the value of Y
is for tomorrow and I just don't undestand

willow bear
#

... this picture looks like the (geometric) definition of a derivative

#

do you have the exact problem statement in writing? i.e. a written specification of what they want you to do?

dusky moon
#

is just find the value of Y

fiery creek
#

Y or y?

dusky moon
#

using the information of the graphic

willow bear
#

well we don't understand what "Find the value of Y" is supposed to mean here either.

dusky moon
fiery creek
#

so you want us to find the function?

willow bear
#

even still...

fiery creek
#

there's not enough given information to do that

willow bear
#

^

dusky moon
fiery creek
#

what

dusky moon
#

find the function

willow bear
#

you're the one with the full problem statement, not us

dusky moon
#

yes, beacuse my teacher asked for the value of y but I also think that's impossible with the given info

willow bear
#

did your teacher ask in writing or orally?

dusky moon
#

he just sent that image

willow bear
#

and only that image

#

and nothing else

#

zero other instructions

dusky moon
#

He often makes tricky questions

fiery creek
#

your teacher off the perc

slow dagger
#

your teacher is stupid

willow bear
#

"Do this for tomorrow."

#

"No, I will not elaborate."

#

"Read my fucking mind or something."

dusky moon
#

absolutely

#

I hate him

#

but is for 50% grade

fiery creek
#

no way that's 50% of the grade impossible

dusky moon
#

Yes it is

#

The whole group is going to fail

willow bear
#

what idiocy

#

you're being SET UP for failure

dusky moon
#

ok, we all agree about my teacher, but I need to solve the problem

willow bear
#

the problem is unsolvable

dusky moon
#

I think is a tricky question

slow dagger
dusky moon
#

i know

fiery creek
#

ok wait

dusky moon
#

find the value of y

fiery creek
#

let me think this through

#

i've seen similar things before in my calc 1 class

#

consider tan(theta)

slow dagger
fiery creek
#

tan(theta) = y/x but you also have similar triangles

#

triangle QPB also has theta as an angle

dusky moon
#

pitagoras?

fiery creek
#

no, similar triangles

slow dagger
#

nmms

dusky moon
slow dagger
#

...

dusky moon
#

ohhh I get it

#

srry

#

I'm just nervous, I don't want to fail

fiery creek
#

can you do what i'm asking

#

@dusky moon

#

have you learned similar triangles

#

and the ratios between the sides

#

@willow bear am i even on the right track?

#

i think they just want an expression for y in terms of the other variables

dusky moon
#

I think if you're doing well. because last month we saw that topic

slow dagger
#

...

dusky moon
#

@slow dagger please help

slow dagger
#

why me?

dusky moon
slow dagger
#

@fiery creek is already helping you bro

dusky moon
#

My teacher stated "Find the value of y"

#

50% final grade

#

and no calculator but fuck up that, i'm using it

willow bear
fiery creek
#

Wait till I get home and then I ca. help @dusky moon

slow dagger
#

you are a hero bro

dusky moon
#

okok thanks man

fiery creek
#

Actually nvm you’re on your own I have homework to do

#

💀💀💀

slow dagger
#

maybe @dusky moon can help you

#

well, you are helping he

dusky moon
#

I'm solving my problem bro

#

if I had time I would help @fiery creek

#

Why don't you help him? @slow dagger you seem to have plenty of free time

slow dagger
slow dagger
#

im just watching this conversation

cold gorge
#

Would the phase shift of y=-5cos(2x+pi) be -pi/2
because C/B=phase shift so it is pi/2 and flip signs because it is out of the parenthesis

pastel fossil
#

B giving me a difficult time, if anyone knows this stuff better

cold gorge
pastel fossil
#

Yeah

#

I have it hold on I don’t have it memorized

cold gorge
#

Think of which quadrant can result in tan being negative

pastel fossil
#

4 and 2

cold gorge
#

yes so how could you get tan to be 1?

#

if you know tan=sin/cos

pastel fossil
#

If tan was 1 the answer would be 4/pi right?

#

I mean pi/4

#

Oh I think I see actually

#

Pi-pi/4

#

Then the answer is 3pi/4

cold gorge
#

yeah

pastel fossil
#

Thanks

cold gorge
weary dock
#

Gunter borrows $1500 at an annual interest rate of 12% and invests all of it at 1% monthly interest rate. approximate the instantaneous rate of change for gunters net gain in 10 years.

#

i dont know if this counts as precalculus but im gonna put this here i think its close enough cuz its grade 11 functions

#

i genuinely dont know how to solve this

#

its out of my math book and I have the answer but nothing i do is getting me it

prime venture
#

12 percent of 1500 is 180

dim orchid
#

can i have help with shown work with these

prime venture
#

✌🏽

rugged crater
willow bear
#

but if you have an attempt for at least one of these, we can take a look and point you in the right direction

wind linden
#

im not sure if i have to simplify this more

#

or if my final answer is good

willow bear
#

$\sin\paren{\frac{24}{25}}$ is not a thing you should be writing here at all

obsidian monolithBOT
#

アンナ

willow bear
#

you are not interested in the sine of 0.96 radians

#

also cos(θ) is negative, since tan(θ) < 0 and sin(θ) > 0.

#

so your "adj" would have beeen -7 and not 7.

#

and cos(θ) = -7/25

wind linden
#

ooh u right

willow bear
#

and then cos(θ) + sin(θ) = -7/25 + 24/25, NOT cos(-7/25) + sin(24/25).

wind linden
#

ooh okay that makes sense

#

so then i would just simplfy those fractions and get my final anwser

willow bear
#

...yes

wind linden
#

thank you! that helped a ton ^-^

#

i need some guidance on this question

#

im not rlly sure on what to do without the arc length or without a degree

willow bear
#

without the angle*, you mean?

wind linden
#

ya lmao

#

i think i can assume that the arc length is 3θ since s=θ(radius) right?

willow bear
willow bear
wind linden
#

oh ok

willow bear
#

the radius is clearly readable as 3 in the picture

wind linden
#

omg

#

i didnt even notice the numbers

#

on the graph cause they were so small

willow bear
#

well there are tick marks

wind linden
#

im not sure if im in the right direction here lmao

willow bear
#

no, you're not

#

for the formula $A = \frac{1}{2} r^2 \theta$, the angle must be in \textbf{radians}, not in degrees.

obsidian monolithBOT
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アンナ

wind linden
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ohh ok

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after i convert it into radians

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do i just plug it in again and do i get my final answer

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or is there still more to it

willow bear
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no, there's nothing else

wind linden
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ooh okie thank you very much :)

low solstice
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yo

viscid thistle
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I hate logarithms goodluck

thorn creek
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start by taking the exponential of each side of the equation, apply the rule that e^(a-b) = (e^a)/(e^b), then apply the rule that e^(ln x) = x

willow bear
low solstice
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no need

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someone helping mwe

weak vessel
weak vessel
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u are taking sin of the answer

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but u have to do sin of theta is 24/25

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not sin of 24/25

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hope it helps

willow bear
tender questBOT
# weak vessel 31/25

As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.

weak vessel
willow bear
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now you do.

weak vessel
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ok thanks

low solstice
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can someone solve this and tell me what the answer u get is

warped cipher
low solstice
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yeah

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i got 4/-5

warped cipher
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seems correct

low solstice
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ok tysm

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can u just make sure cuz i dont trust myself

warped cipher
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I am sure

low solstice
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ok ty

warped cipher
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check alpha if needed

willow bear
solar olive
tender questBOT
solar olive
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So i derived this and i was wondering if theres a way i can also derive a partial fraction decomposition for 1/(1+x^N)

fading monolith
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I think there is a easy way using complex numbers

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For 1/(1+x^N) I would say power series

solar olive
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Though i derived a general case with complex number, i want to try with real numbers

pastel fossil
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I have to compare the graphs of sin and cos with tan and find the similarities between them, so far I got that all 3 graphs are periodic, exhibit repetitive patterns, and exhibit symmetry, are these bad answers?

solar olive
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cos and sin are translations of eachother

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due to the fact that cos(pi/2 - x) = sin(x) and sin(pi/2 - x) = cos(x)

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etc

pastel fossil
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Oh I see, so periodic would be a “synonym” of repetitive pattern

solar olive
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sort of yeah

fading monolith