#precalculus

1 messages Ā· Page 98 of 1

daring osprey
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ah

round geyser
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Yes

neat sundial
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Oh okie so power rule !

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I know basic formulas...

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I rather need techniques..

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Like they transform the whole integral to something 😭

ancient inlet
chilly arrow
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and i didnt say it was impossible, just not really doable by normal methods

round geyser
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Do they have period and amplitude

neat sundial
ancient inlet
manic crest
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Calculas is the EASY CHAPTER

round geyser
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I’m graphing csc and sec

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It’s just inverses of sin and cos

uncut mulch
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careful with the use of "inverse"

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make sure to mention multiplicative inverse

hushed sphinx
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"Reciprocals" is even better.

dry verge
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Are linear algebra concepts like linear transformations usually taught in precalculus?

tame shard
dry verge
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It's like an "intro to linear algebra" course in a way, even if it's in precalculus.

pale oracle
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its precalculus

pale oracle
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yeah..cuz its precalc

valid topaz
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<@&268886789983436800>

round geyser
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Is there is amplitude in front of csc/sec x

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Make a guide graph of sin/cos x

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Place them there and draw asymptotes or poles

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And draw ā€œparabolaā€

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Check my work

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Mine got skewed

undone pumice
round geyser
undone pumice
round geyser
undone pumice
undone pumice
round geyser
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Now I have period of pi and quarter period of pi/4

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And then Horizontal shift is none

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Where to start

undone pumice
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yup (but remember that the period is over 2 set of asymptotes)

round geyser
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0? then pi/4

undone pumice
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first

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think about how sec is the reciprocal of another trig function

round geyser
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I graph the cos 2x as a guide graph

undone pumice
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mmhm

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(3cos2x, not cos2x)

undone pumice
round geyser
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Like this

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That’s what my teacher taught

round geyser
undone pumice
round geyser
undone pumice
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ye

round geyser
#

I start with the horizontal shift

undone pumice
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it touches so its useful to draw the cosine

round geyser
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Then add quarter period

undone pumice
#

uh i dont know

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i never learned all this quarter period bs

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i just learned how to graph

round geyser
undone pumice
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ikk

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i just dont like that

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term

round geyser
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Where do u start

undone pumice
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for which function?

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sin/cos or the ones with asymptotes

round geyser
#

Evelyn what are some advice about graphing tan and cot

undone pumice
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uh

round geyser
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Since I’m learning that tmr

undone pumice
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they look very similar just reflected versions moved differently

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like

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cot looks like tan

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if it was reflected over the y axis

round geyser
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It it’s sin x over cos x

undone pumice
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and it was shifted pi/2 (cus cot=cos/sin and sin has diff zeroes)

round geyser
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0 1 0 -1 0
1 0 1 0 1
0 und 0 und 0

undone pumice
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ye there will be asymptotes

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period of pi

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and then

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pi/4 and its other angles are useful(cus tanpi/4 is just 1, right?)

round geyser
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the main I use is

undone pumice
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so you can use 1, -1 for tan from -pi/4, pi/4

round geyser
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0, pi/2, pi, 3pi/2, and 2pi

undone pumice
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tangent has a period of pi

round geyser
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Asymptotes of tan will be at pi/2 and 3pi/2

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It’s asymptote of tan = (odd number)*(pi/2)

undone pumice
round geyser
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also 5pi/2, 7pi/2, 9pi/2

undone pumice
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my teacher taught us using

round geyser
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Like I put
(radians)=(degrees) * pi/180
(degrees)=(radians)* 180/pi

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Cool

round geyser
undone pumice
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mm k

round geyser
#

Now ik

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period = 4*quarter period

undone pumice
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um

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ye

round geyser
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So on and so fourth

undone pumice
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so period shift but no horizontal dilation

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vertical dilation

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no vertical shift

round geyser
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Do I start at pi/4

round geyser
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Then add pi/2?

undone pumice
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wdym by that

neat path
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Im a 9th grader

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And i came across this equation of making a heart shape

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(X^2+y^2-1)^3 - x^2y^3=0

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And i was wondering whether integrating from 0 to x and 0 to y will completely fill it up?

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Im trying to learn all this and i think this is how you do it so can someone please explain it to me

rancid mason
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do you have a diagram?

rancid mason
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find its range

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as shown the range is from -1 to 1

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its possible but its not for this channel

neat path
rancid mason
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you have to make the function to only have x

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otherwise it wouldnt be possible

neat path
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Why cant we integrate both x and y

rancid mason
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you need to intergrals then

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which is very hard to do

neat path
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Okayy

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Thanks

rancid mason
# neat path Thanks

so all you need to do is to make this equation into a function with y being the subject

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and then intergrate it from -1 to 1

regal tangle
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sqrt(x) does the limit exist at 0 ?

tame shard
hushed sphinx
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Yes, but some textbooks only define limits for functions that exist in an entire deleted neighborhood of the target point.

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That's not any kind of deeper mathematical truth, though, only an attempt to save complexity because it takes a bit more explanation and notation to define them more generally..

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What? Where?

hushed sphinx
hushed sphinx
obsidian monolithBOT
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Troposphere

neat path
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So as he said, we create a function f(x) = that?

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Could you please explain

hushed sphinx
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Writing f(x) = (x^2+y^2-1)^3 - x^2y^3=0 would not make sense, because what you put to the right of "f(x) =" should be an expression rather than an equation.
You can write f(x) = (x^2+y^2-1)^3 - x^2y^3, but that still doesn't give you a function until you decide on a value for y.
You can write f(x,y) = (x^2+y^2-1)^3 - x^2y^3, but (a) that now is somewhat far removed from your heart-shaped curve, and (b) integrating a function of two variables is not a single thing -- that is there are several possible concepts it could mean.

neat path
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Oh

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So if we find an expression that gives us the heart shaped curve IN THAT X VARIABLE, then we can integrate it from 0 to x, filling the shape up?

hushed sphinx
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It's also not quite clear to me what you mean by "filling the shape up".
I suspect perhaps instead of integration what you want might just be the inequality (x^2+y^2-1)^3 - x^2y^3 <= 0, which makes the solution set include the interior of the heart.

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Or are you trying to compute the area of the heart shape?

neat path
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I was maybe thinking of the same shape but a tiny width smaller than the last all the way until 0, which would make it not only 1 heart shape but "filled up" in the sense that it is completely coloured. And i figured that using integration could perhaps give that small width needed to complete the fill up?

twin eagle
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where does number theory go?

hushed sphinx
hushed sphinx
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No, I was replying to the other person with the weird name there.

neat path
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Hes my friend from school

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Yeah @hushed sphinx so my question wss

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Was

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Hope you understand

hushed sphinx
neat path
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But i want infinitesimally small hearts inscribed in each other

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Like concentric circles perhaps, but with the width in between them almost 0

hushed sphinx
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Okay, that is definitely not something where the concept of "integration" is relevant.

neat path
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Oh, okay. Could you tell me how to do that though?

round geyser
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Wow

hushed sphinx
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You can get a family of curves that fill out the heart by setting the right-hand side of the equation to different negative values instead of 0. However, as this plot shows, they behave somewhat wonkily around the axis crossings -- In fact, I don't completely understand how the original manages to look nice and smooth around the x-axis crossing.
I don't immediately know how one would create neat equations for curves at a constant distance from the heart shape. That is in general a hard problem that cannot be done with polynomials.

round geyser
jolly karma
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Would anyone perchance know how to find the focus of a parabola?

hushed sphinx
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What do you already know about the parabola? Equation, or some points on it, or a drawing in the plane and you have straightedge and compass?

honest meadow
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is the parabola aligned to an axis?

regal tangle
hushed sphinx
regal tangle
hushed sphinx
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It would be something like the limit of f(x) for x->c is a number L such that

for every epsilon>0 there exists a delta>0 such that for each x with 0<|x-c|<delta and f(x) defined we have |f(x)-L|<epsilon.
and then with a caveat that the concept doesn't make sense (because L would not be unique) unless c is a limit point of the domain of f.

round geyser
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Hey I need help for doing y=-5 cot 8x

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Amp: None
Period: pi/8
Quarter point: pi/32
Vertical shift: none
Horizontal shift:none

hushed sphinx
round geyser
manic crest
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If 7x+2y=4, 128^xƗ4^y=?

SAT sneaky question

tame shard
manic crest
manic crest
tame shard
manic crest
tame shard
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You realize that 128^y = 2^7y, 4^x = 2^2x?

manic crest
tame shard
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And standard logs?

manic crest
tame shard
#

Fyn standard

tame shard
manic crest
tame shard
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You know logs arent constrained to base 10 or base e right

manic crest
tame shard
manic crest
obsidian monolithBOT
#

ishantgaming67

manic crest
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Bruh

tame shard
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Define log 4 of x

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Cuz im pretty sure we do not understand each other

uncut mulch
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Natural Logs: In_4(5)
makes no sense

tame shard
manic crest
tame shard
manic crest
tame shard
manic crest
#

Homophobic?

tame shard
# manic crest Homophobic?

since dagestan is a muslim region, they are homophobic there, getting send to dagestan implies you are going to get the gay beaten out of you

uncut mulch
leaden portal
tame shard
#

You know plenty of memes out there are in fact bigoted

round geyser
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Easy

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128^x = 2^(7x)
4^y = 2^(2y)
2^(7x) * 2 (2y)
2^(7x+2y)
2^4 ; (7x+2y)=4
128^x * 4^y = 16

round geyser
#

Ye

round geyser
tame shard
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Idk what that guy was up to tho with the log_4 shit

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And wth is a jungle method

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Vro never explained that

round geyser
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Can you check this please

round geyser
round geyser
novel delta
round geyser
novel delta
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I thought it was cosine, sorry then this is correct

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for the second one i do not know about how your teacher structures things however I believe its more preferable to say pi/6 right rather than -pi/6 and for VS it is 1 unit up. But that is just communication other than that everything checks out and is correct.

round geyser
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Then it’s pi/6 + the quarter period

novel delta
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That should be where the next increment is located. the period + quater period , then plugging that in will give you the y

round geyser
novel delta
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HS ± quarter-period gives you the key points for one full cycle (the one you actually sketch). Adding the period just moves you into the next repeated cycle, it gives the same type of points, just shifted right.

round geyser
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Then it’s 14pi/48?

novel delta
round geyser
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Ok

round geyser
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That’s what I got so far

novel delta
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No that is not the asymptote that is the important points where the tangent hits a specific y value after the transformation the asymptote is at x = -pi/12 and 5pi/12

round geyser
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Ohh

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So I add pi/2

novel delta
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Almost, you have to solve when the inside of the tan is equal +- pi/2

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So solve 2(x-pi/6) = pi/2

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that will give one of the asymptote

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the general is 2(x-pi/6) = pi/2 +k*pi

round geyser
#

Okay

round geyser
#

x=pi/6 + pi/4
x=10pi/24
x=5pi/12

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Don’t laughs at my sketch

scarlet cedar
round geyser
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That’s why

scarlet cedar
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No worries there

round geyser
#

But is that right

novel delta
round geyser
#

Yay

novel delta
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And other than the drawing the tangent graph seems correct

round geyser
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Okay

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I think graphing trig functions are interesting

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Like doing sec and csc

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It’s like a parabola

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And cot is like cubic

novel delta
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Well cot is -\tan\left(x-\frac{\pi}{2}\right)

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-tan(x-pi/2) for cot(x)

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So especially the identites they are interesting and can aid later on in more higher mathematical sectors as they help simplify many equations.

round geyser
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Yep

timber jasper
#

Can someone give me some basic limits questions (infinity included) (please don’t include cubes conjugates and trig I’m trash in them)

oak night
# timber jasper Can someone give me some basic limits questions (infinity included) (please don’...

Here are some basic ones without trig, conjugates, or cubes

  1. lim x->2 (3x+1)

  2. lim x->4 (x^2 - 16)/(x - 4)

  3. lim x->3 (x^2 - 9)/(x - 3)

  4. lim x->-1 (x^2 + 3x + 2)/(x + 1)

  5. lim x->0 (5x)/(x + 2)

  6. lim x->infinity (2x + 1)/(x + 4)

  7. lim x->infinity (3x^2 + 2x)/(x^2 - 5)

  8. lim x->infinity (4x + 7)/(2x^2 + 1)

  9. lim x->infinity (5x^2 - 1)/(x + 3)

  10. lim x->0+ 1/x

  11. lim x->0- 1/x

  12. lim x->2 1/(x - 2)^2

  13. lim x->2+ 1/(x - 2)

  14. lim x->2- 1/(x - 2)

  15. lim x->infinity (7 - 3x)/(2x + 5)

obsidian monolithBOT
#

Civil Service Pigeon

timber jasper
#

I’ll save it with myself

round geyser
round geyser
tame shard
round geyser
tame shard
round geyser
#

sqrt(6)

tame shard
#

$\lim_{x \rightarrow -1} \sqrt{x^2+5}$

obsidian monolithBOT
#

P(this user is larp larp) ≄ 0

tame shard
#

This is trivial

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Just sub -1 in

round geyser
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Yea that was the way I solve these

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$\lim_{x \rightarrow -1} \sqrt{(-1)^2+5}$

obsidian monolithBOT
round geyser
#

$\lim_{x \rightarrow -1} \sqrt{x^2+5}$=$sqrt{(-1)^2+5}$=$\lim_{x \rightarrow -1} \sqrt{6}$

round geyser
tame shard
#

Since you are substituting x in anyways

round geyser
#

Can you show me please

obsidian monolithBOT
tame shard
#

$\lim_{x \rightarrow -1} \sqrt{x^2+5}$ \
Substituting x = -1 in we have \
$\sqrt{(-1)^2+5} = \sqrt{6}$

round geyser
#

Thanks

obsidian monolithBOT
#

P(this user is larp larp) ≄ 0

little surge
#

Cmon guys y'all can solve ur questions šŸ”„

round geyser
valid topaz
#

uhh well if we rearrange and divide by x we can see that x=2 is a solution

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there has to be a second one too by ivt

round geyser
valid topaz
#

uhh i dont think we can use that here

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atleast i can't manipulate it into that form

undone pumice
#

(x^x)/x = 2 for the integer solution. then for the other solution

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take the natural log

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but im pretty sure its um

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a transcedental equation

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from my knowledge

round geyser
#

x^x=2x
x=log_x 2x

undone pumice
#

Uhhh yeah so it ended up as like a transcedental equation type situation

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where you can't reallllyyyy algebraically solve it

round geyser
#

Then the only way is to plug and check

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Ik exponential functions’s domain is x>0

undone pumice
round geyser
#

I plug 2
(2)^2 - 2 =2
2=2

undone pumice
#

ye so 2 is the first solution

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theres another

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uhhh i guess if you rewrite it

round geyser
#

Idk what’s their exact form of 0.34632

undone pumice
#

as (e^lnx)^(x-1)=2

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cus e^lnx=x

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as such $e^{\left(x-1\right)\ln x}=2$

obsidian monolithBOT
#

evelyn \\ HS 9

round geyser
#

Take ln

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(x-1) ln x = e^2

undone pumice
#

i would do like substitituion maybe

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cus lambert w wants ue^u structure

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so like maybe if u = lnx

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(e^u)(e^u-1)= e^(ue^u-u)=2

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$e^{\left(ue^{u}-u\right)}=2$

obsidian monolithBOT
#

evelyn \\ HS 9

undone pumice
#

ue^u-u=ln2

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hmm nvm actually... lemme think of a diff way to force a lambert

valid topaz
#

apparently there exists smth called the r-lambert function

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that might work

undone pumice
#

hmm

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haven't heard of that one before

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rn im attempting to force this silly equation to be a lambert

valid topaz
#

i don't think that's possible cuz it becomes (x-1)lnx=ln2

undone pumice
valid topaz
#

huh how

undone pumice
#

first i raised it by uhh

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wait lemme grab some paper

valid topaz
#

nvm i have dinner

undone pumice
#

1/x-1

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ah seeya

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a bunch of substitution work and stuff mostly just weird manipulation

valid topaz
#

hmm

undone pumice
# valid topaz huh how

(ts is not fitting on the small paper i have-) okay so basically first i substituted y=lnx which gave (e^ye^y)-1=2 or e^ye^y-y=2

valid topaz
#

alr

undone pumice
#

Then I took the natural log

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so ye^y-y=ln2

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Then factor out the y

valid topaz
#

y(e^y-1)=ln(2)

undone pumice
#

sub in u=-y

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and then mult both sides by -1

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and then multiply both sides by e^u

valid topaz
#

u(1-e^u)=-e^uln(2)?

undone pumice
#

i wrote it like that

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then isolate the u

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so add ue^u to both sides

valid topaz
#

ok

undone pumice
#

Lwk my Chromebook just died but here’s the next few steps

#

I didn’t know what letter to pick so uh ye I substuted in an a

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After more manipulation got it into ae^a form which is lambert w

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And then from the first substitution y=lnx it got kinda squished in the corner but

valid topaz
#

ok gimme a sec to read over this

undone pumice
#

Kk if I made a mistake lmk lwk tried like four approaches until I got a lambert form šŸ„€

valid topaz
#

so u tried to apply the lambert w to a*e^a=a/2+ln2/2?

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there's a linear factor in the RHS

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wait

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so i tried back-subbing the final value in and it didn't check out

round geyser
#

Anyways

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Is this correct

raw hill
#

In the future you may want to be more careful about mixing signs on your shift

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Using ā€œleftā€/ā€œrightā€ also works

round geyser
#

It goes right pi/2

raw hill
#

Or left pi/2 since pi/2 - pi = -pi/2

round geyser
#

Ohh

raw hill
#

Hence why I said it was fine in this case even though you mixed negatives and positives

round geyser
#

For graphing

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My teacher wants us to make Horizontal shifts the same denominator as the Quarter period

raw hill
#

That’s not what I’m talking about

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I’m talking about how you wrote a negative and dropped it

round geyser
#

I should’ve wrote ā€œleftā€

#

Do I add pi/4

raw hill
#

adding pi/4 to what

round geyser
#

pi/4 + 2pi/4

round geyser
raw hill
#

um I mean you can add anything you want to

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What are you trying to accomplish

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I’m not following

round geyser
#

I want the next point

raw hill
#

uh ok ig yeah

karmic brook
round geyser
#

Tan has no amplitude

karmic brook
#

oh yeah

#

whoops

#

for adding points to the graph. ecspecially with tan where its a bit wonky, plot the asymptotes first and then the x intercepts. and then the rest of the graph doesnt have to be exact just follow the shape of the function

karmic brook
# round geyser Do I add pi/4

so pi/2 is an x- intercept but so is pi/2 +kpi (k belonging to intergers), so you need to plot (pi/2, 0) but also anyother x intercepts that fall into the graphs domain

#

and then draw the behaviour around the nearby asymptotes

round geyser
#

So is it (pi/2,0) the point

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I’m trying to add quarter points easier so I made the HS 2pi/4

karmic brook
round geyser
#

Ok

round geyser
#

pi/2

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Specifically right pi/2

karmic brook
#

no like what does it stand for ?

round geyser
karmic brook
#

oh okay

karmic brook
#

you dont really need to split it into quarter points

round geyser
#

It’s 2pi/4, 3pi/4, pi

#

What would this be

karmic brook
#

not 3pi/4

undone pumice
# round geyser

*right pi/2, not left. graph will look the same i beelive for left or right but...

#

Oh and also yeah. If the zeroes of the parent tangent function are -pi/2, pi/2, 3pi/2, shifting pi/2 right just makes it like 0, pi, etc

karmic brook
# round geyser

and again you dont need the quarter points, they dont really add much, since they dont show anything special about the graph

#

make sure to label your vertical asymptotes with the equation of the asymptote as well

undone pumice
#

yeah or just give the equation of the general placement of the asymptotes (like the set theory notation i showed u)

karmic brook
round geyser
undone pumice
#

which in this case would be x=0/pi/2pi/whatever starting point + pi k (or n, or whatever variable you want) where it is defined as an integer...

undone pumice
# round geyser

*right pi/2. graph looks the same right or left but if you want to get technical its shifted to the right pi/2 and if you're being graded on whether you wrote the right direction..

round geyser
undone pumice
#

wait one more thing

#

3pi/2 is not in the middle of 0 and pi

#

label that one as pi/2

karmic brook
# round geyser

from that it looks like you have a vertical asymptote at 3pi/2, your behaviour of your graph around asymptotes needs to be shown (bring the line closer to the pi)

undone pumice
round geyser
#

I meant this

undone pumice
#

that is also incorrect

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it crosses at the point in between 0 and pi

#

which would be where you have marked 3pi/2, which is incorrect (redraw your graph, and also relabel)

round geyser
undone pumice
#

... well i guess that works too

round geyser
#

So I can have

#

3pi/2

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As a point

#

It’s (odd number)*pi/2

karmic brook
# round geyser It’s (odd number)*pi/2

technically right but the more correct way to write this is pi/2 +kpi (k belonging to intergers) or if you are really adament with that odd number write it as (2k+1)pi/2 (k beloginging to intergers)

#

and just search up the math symbol and set notation for beloging to intergers

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its like a weird E into curly brackets

undone pumice
#

Ummm I showed him before

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Yeah and that z symbol

karmic brook
undone pumice
#

Sigh

winter osprey
#

Graphing trig functions that aren't sin and cos 🤢

karmic brook
winter osprey
#

i guess bro šŸ˜’

lost rivet
#

How do u do no8? I did dy/dx to get the negative reciprocal for the normal gradient

round geyser
#

I was taught
Graphing sin and cos
Graphing csc and sec
Then
Graphing tan and cot

lost rivet
raw hill
round ermine
manic crest
#

4^x=x?

tame shard
#

,w 4^x=x

obsidian monolithBOT
tame shard
#

Yup

tough flare
tough flare
tame shard
#

1+2+3+...+n = n(n+1)/2

tough flare
#

What's correct for $|S \cross S|$?

obsidian monolithBOT
#

Ujjawal Gupta

tame shard
tough flare
tame shard
#

In that one example

#

S has 2 elements

#

There is like 4 ways to pair 2 elements together

#

So 2^2

tough flare
#

What if it has n elements?

tame shard
#

(Looking at it, its nicely related to pascals triangle too)

warm panther
#

Should I use the quadratic formula to solve for x in quadratic equations?

tame shard
#

Like

#

Its literally made for that

echo sinew
manic crest
#

Y=the equation, Y=X

tame shard
#

Desmos

#

Err

#

The lambert W function extends to complex solutions too

#

Desmos cant do that

warm panther
tame shard
#

But almost all quadratics are not factorable

warm panther
#

Really

tame shard
hybrid zodiac
#

Is there a way to solve x^x=a without using lambert w?

#

Cause im not really accoustumed to using lambert w so im really unsure if what i did was correct or if there was a better way

hushed sphinx
#

That's pretty much what the W function is (up to some logarithms).

#

However, you may count numerical methods (such as bisection) for root finding as "a way to solve".

#

That's how the W function itself is computed, anyway.

hybrid zodiac
#

I understand,thanks.

tame shard
#

,w

round geyser
manic crest
tame shard
raw hill
obsidian monolithBOT
#

Civil Service Pigeon

round geyser
#

I plugged in x=2 it works

#

So -2

raw hill
#

well yes those two work, but I'm assuming you want a fully rigorous solution to show that there's no more

round geyser
#

I thought it’s (5+sqrt(24))^-1

raw hill
round geyser
#

It’s -2<x>2

round geyser
raw hill
#

Both terms on the left are exponential functions with positive base

#

meaning that both terms on the left are defined for all real x

round geyser
#

Okay

round geyser
#

But with discriminate > 0

raw hill
#

but it's not really a parabola

#

,w graph cosh x

obsidian monolithBOT
raw hill
#

Rather it's a transformed version of the cosh graph (I'll let you figure out the actual transformations)

#

$$\cosh x=\frac{e^x+e^{-x}}{2}$$

obsidian monolithBOT
#

Civil Service Pigeon

round geyser
#

Ik (1+1/x)^x=e

raw hill
#

the limit of that is e, yes

umbral timber
round ermine
#

hyperbolic cosine

raw hill
#

Yeah that's how the hyperbolic functions are notated. So sinh is hyperbolic sine, tanh is hyperbolic tangent, etc.

round geyser
#

Ohh

#

I only know to how to graph sin, cos, tan, csc, sec, cot

round ermine
#

i think hyperbolic trig is a little outside precalc level though

round geyser
#

I agree

raw hill
#

eh it's just linear combinations of exponentials which they should be familiar with, no?

#

so it should be fine up to the one piece of new terminology

round geyser
#

Cuz I just got to graphing tan and cot

raw hill
#

though the hyperbola background is a whole rabbit hole of its own

round ermine
#

and proving that representation is definitely outside precalculus level but it’s nice to know

undone pumice
round ermine
#

i only know that cosh creates catenaries which show up in hanging chain problems
other than that you can graph them but i'm not aware of any special names for them

round ermine
round geyser
#

Taking their conjugates

#

And difference of squares

round ermine
#

really useful for systematically solving the original problem

#

since of course that means you can represent one of the terms as the other term raised to the -1

loud juniper
#

am i able to learn pre without understanding algebra that well

undone pumice
#

i would sayyyy its possible buttt i would not recommend it if you can take some time to review like alg2 stuff over summer or something like

round geyser
#

Look that’s what my teacher taught us

undone pumice
round geyser
#

The

#

p(x)=tan(x-(pi/2))

undone pumice
#

ah

round geyser
#

I meant to do 4 tick marks

winter osprey
#

aint no one tryna graph trig functions anymore

round geyser
round geyser
#

Good luck graphing them

winter osprey
#

i always hated graphing in precalc and alg2

#

i mean i could do them but it was just tedious and annoying

undone pumice
round geyser
undone pumice
#

ik... but like...

#

the period is still pi so it shouldn't be in units of 1, 2, 3, 4 ...

#

i mean its not that bad

#

ill go graph it rq will see how long it takes

winter osprey
#

labeling with integers when doing trig funcs is so nasty 🤣

undone pumice
#

kinda hard but just imagine at -pi/4, -3pi/4, pi/4, 3pi/4 the y is 1/3, cus its hard to make it look like that

winter osprey
#

i dont miss that shit one bit gang

undone pumice
round geyser
undone pumice
#

like last month

undone pumice
#

and you didn't shift it

#

the asymptotoes of parent tangent are at -pi/2 and pi/2

#

so when its shifted its supposed to move

#

and tangent is strictly increasing in between asymptotes

round geyser
#

Is it pi and 0

undone pumice
#

yea

undone pumice
round geyser
#

I was look at this

undone pumice
#

cotangent as i mentioned before looks like tangent but reflected horizontally and has different asymptotes

round geyser
#

I though I start at -pi/2

#

Then make it -2pi/4 and add pi/4

undone pumice
winter osprey
#

did yall have to use the rational root theorem

#

at all in ur class

undone pumice
#

dont get me started

#

it'd be like 24 and 2 or something

#

and my teacher made us guess and check every value with synthetic division

#

not in precal tho

winter osprey
#

teach gave us a 6th degree poly and told us factor it, the constant term as a 24 or something that had a bunch of options

undone pumice
#

in that other course, integrated 2

undone pumice
#

couldn't have been 20 or something

winter osprey
#

fr

round geyser
#

I got that too

#

I love rat theorem

round ermine
undone pumice
#

for me

#

ts pmo

#

glad we didin't use it this year at least

round ermine
#

i was taught like some rules that helped eliminate certain terms but i forgot them all

winter osprey
#

same here

round geyser
round geyser
#

Which made it quicker

#

Get the two roots

#

Choose one do synthetic

#

And done

undone pumice
#

we had to just

#

guess

#

no calculator allowed

winter osprey
#

we were only ever allowed scientific calcs, never graphing

undone pumice
# round geyser

you still have it written down as "right pi/2". graph looks right, make sure when you label its clear which tick mark is that value because it kinda looks like the one above where it's supposed to be

undone pumice
#

learned RRT in integrated 2 so was just like... "is x-1 a root" no its not "okay lets try x-2" going off vibes until u got one

round geyser
#

Also that unit was the first unit in pre-calc to get an 100

undone pumice
#

nice

#

didn't go over rrt in precalc tho at least so

#

yay

round ermine
# round geyser

why is y=1/3 1 unit above the x-axis and y=-1/3 is 2 units below

round geyser
#

That’s what was my question

round ermine
#

they should be the same distance from the x-axis though assuming your scale represents each unit as a change of 1/3

foggy steeple
#

yo so like im working on sigmas but im lowkey clueless on how to find these darn formulas

#

i mean like it gives me a series or sequence and the answer key has something completely different than what i put

round geyser
round ermine
# round geyser

systematic solution
||rearrange: k^3-k^2+36=0. rational root theorem: roots could be ±1, ±2, ±3, ±4, ±6, ±9, ±12, ±18, ±36. test them, you get -3 is a solution: (-3)^3-(-3)^2+36=0 -> -27-9+36=0 -> 0=0. so (x+3) is a root. polynomial division: (k+3)(k^2-4k+12). solve for zeros of quadratic: k= 2±2i√2||

modern yarrow
#

Can anyone tutor me? I'm working on derivatives in my precalc class

ionic temple
undone pumice
#

im in precalc too, i can try to help u

modern yarrow
#

product rule, quotient rule, second derivatives, chain rule

undone pumice
#

oh wow i see

#

alr so which parts dont make sense

#

do you not understand how/when to apply the rules or is it like more you dont get the concept/intuition behind stuff

modern yarrow
#

well its not that they dont make sense, I was absent last week for some personal stuff and now I have to learn the whole unit before the test tomorrow

undone pumice
#

oh i see

#

uhhh

#

so do you know the rules?

#

if not ill go over them and try to give u some examples

modern yarrow
#

I think I got the product rule down, Im trying to learn the quotient rule atm

#

im just learning as I do my papers I missed

undone pumice
#

if you look at quotient rule its actually very similar to product rule

#

in the numerator

#

like if you have say f(x)/g(x) its the same thing except you have to put the derivative of f before g and theres a minus sign instead of plug

#

and then divide that by g(x)^2

modern yarrow
#

Okay, thank you!

undone pumice
#

you're welcome

#

if you want more help ill be lurking here while i play some brawl stars

modern yarrow
#

Okay!

winter osprey
#

make sure you do it in that order, because if you choose to do g'f - f'g it will switch the sign

#

for the numerator that is

scarlet cedar
round geyser
#

This one is 100% easy

#

What do u get

small estuary
#

3

round geyser
#

And hint use difference of cubes

#

lim x-> 1 ((x-1)(x^2+x+1))/(x-1)
lim x-> 1 ( x^2+x+1)
(1)^2+(1)+1= lim x-> 1 3
D

#

That’s my step

small estuary
#

yeah, thats the most logical solution

round geyser
#

I would say this is the basic of pre-calc

small estuary
#

ts is way too easy

#

but for instance the kinf od limits that include recursice functions are just pure labor

round ermine
round geyser
round ermine
#

we were just taught limits of polynomials as x->infinity or -infinity

small estuary
#

nah those are eay too

small estuary
#

but like did you learn undefined cases?

round geyser
#

Like this

#

It’s just -1

round ermine
#

oh that’s just figuring out horizontal asymptotes

round geyser
#

-x^2/x^2 = -1

small estuary
round geyser
round ermine
round geyser
#

Yea that’s what I did

round ermine
#

but that was really early on and i don’t think anybody remembered anything about it

#

other than me

#

because it’s a little more relevant in calculus

round geyser
#

Check

round ermine
#

forgot that last step

#

whoops

small estuary
round geyser
#

3^2x + 4^2x= 7^2x

ancient inlet
#

hmm

#

x = 1/2 ?

round geyser
#

Yes

#

It is 1/2

dire otter
#

anyone open for practice?

round ermine
#

god damn you are in a lot of gacha servers

dire otter
dire otter
round ermine
#

i am currently going to class

chilly arrow
#

but then they put it in the exam 😭

#

did you do sinx/x

round ermine
#

i learned it on my own and i know it equals 1 but no

round geyser
#

Hey is zero also an asymptote specially vertical

dire otter
round geyser
#

That’s should’ve been

tame shard
#

,w 49^x=9^x + 16^x

#

No lambert w suprisingly

obsidian monolithBOT
round ermine
#

i mean if you simplify it down to 3^(2x)+4^(2x)=7^(2x) you can recognize that 3+4=7 so 2x has to equal 1

round ermine
#

i’m not entirely sure how you would more rigorously solve it though

tame shard
#

Or lambert w function but idk

round ermine
#

i don’t know how logs would help

tame shard
#

But like log(x^y) = y log (x), but the damn addition term

dire otter
tame shard
# dire otter why

we can only help you with the questions, not outright give you the solution or do your hw

dire otter
dire otter
tame shard
dire otter
#

problem 3 and 4 uses traditional integration techniques

tame shard
# dire otter so can u solve it or not

no, but if you ask it in #calculus someone might be able to help you. Please note, we can only help you with solving the questions, not outright give you the solution or do your homework for you.

dire otter
tame shard
#

we dont give out solutions in general

#

where did you even get that conclusion from?

dire otter
tame shard
#

you would know if you read #rules

jolly karma
#

How do I determine which value the foci is attached to when working with Ellipses?

#

Value as in x or y

round ermine
#

the foci will always be on the major axis
in other words you’ll need to determine whether the ellipse is oriented horizontally or vertically and from there you can determine where the foci are located (y for vertical, x for horizontal)

round geyser
#

What’s this mean

round geyser
#

What’s the asymptote for parent graphs for tan x and cot x

raw hill
#

,w asymptotes of tan x

obsidian monolithBOT
raw hill
#

,w asymptotes of cot x

obsidian monolithBOT
raw hill
#

sully odd way to write it but ok

#

$y=\tan(x)$ has asymptotes at $x=\frac{\pi}{2}+n\pi$ and $y=\cot(x)$ has asymptotes at $x=n\pi$ ($n$ is an integer.)

obsidian monolithBOT
#

Civil Service Pigeon

raw hill
#

This is immediate from noting that $\tan x=\frac{\sin x}{\cos x}$ and $\cot x=\frac{\cos x}{\sin x}$ and considering where the denominators are equal to $0$

obsidian monolithBOT
#

Civil Service Pigeon

raw hill
#

@round geyser

round geyser
#

Yes

#

Between 0 and 2pi

#

Is it gonna be pi/2 and 3pi/2

#

While cot x is 0 and pi/2?

round geyser
#

x=0

raw hill
#

eh depends on how precise/colloquial you're being

#

"between" usually means you exclude the endpoints

round geyser
#

And x=pi

raw hill
#

but if you're talking about the closed interval $[0,2\pi]$, then $y=\cot x$ has vertical asymptotes at $x=0$, $x=\pi$, $x=2\pi$.

obsidian monolithBOT
#

Civil Service Pigeon

raw hill
#

If you're talking about $(0,2\pi)$, then just $x=\pi$

round geyser
obsidian monolithBOT
#

Civil Service Pigeon

round geyser
#

I would start at horizontal shift then add in quarter period

orchid urchin
undone pumice
orchid urchin
undone pumice
#

uhhh

#

matrices?

orchid urchin
#

thats an interesting one ngl

undone pumice
#

i understood most of what we learned from prior courses

undone pumice
#

its just like... mostly cus i didn't really learn them before. having to learn stuff like unit vectors and stuff is just new and a bit hard to understand

orchid urchin
#

yeah I see how, personally for me its mostly probability and statistics

undone pumice
#

oh

#

we aren't learnng that in our precal course

#

i only know like probability up to normal distributions and stuff

#

bell curve thingy

orchid urchin
#

dam, its good because it shows how set theory becomes practical in probability

undone pumice
#

from prior course

orchid urchin
#

used to be just stuff I learned for proofs

undone pumice
#

oh

orchid urchin
undone pumice
undone pumice
#

i didn't learn that in precal tho

#

a course called integrated math 3 that i took last yr

orchid urchin
#

yeah imo statistics is like the physics of math if that makes sense, you learn just like a base foundation and then way later you build on with way more advanced stuff (calculus)

undone pumice
#

mm icic

#

interesting

orchid urchin
#

well depending on the major

#

that is

undone pumice
#

ah

#

my teacher told us we should take ap stats or calc next year depending on our major but i didn't really know so i js picked calc

orchid urchin
#

yeah calc easily because calc is everything, calculus and linear algebra are top fucking tier, especially once you see how they are interconnected a bit, it be crazy enlightening in differential equations

undone pumice
#

ah

#

interesting

winter osprey
#

calc is good

#

i didnt like AP stats but i still got an A in it

round geyser
round ermine
#

stats is that one math subject i’m never interested in whenever it’s taught in classes

chilly arrow
#

is limits even precalc and not calc

round ermine
chilly arrow
#

i feel like u just need some interesting questions

round ermine
#

but calculus dives much more deeply into limits

chilly arrow
#

right

round geyser
#

Wrong section

dry verge
#

Should I assume that the vectors' angles equal 0, 90, 180, and 270, respectively?

astral apex
round geyser
echo sinew
round geyser
#

My first idea was combine from left to right

#

Like combine ln 3 -ln (x+5)

#

Info ln(3/(x+5)

echo sinew
#

Yup correct move šŸ‘

round geyser
#

But then it’s getting stacked into a fraction tower

#

So my second idea was

echo sinew
#

Make sure, though, to check the domain of the whole equation (better if you do it at the beginning)

round geyser
#

y > 0

#

Now is 0 > y > -5

echo sinew
round geyser
#

If I’m correct

round geyser
#

Now is ln 3 - ln (x+5) = ln x

round geyser
echo sinew
round geyser
#

ln cancels
3/(x+5) = x

round geyser
echo sinew
#

Yes

#

Which unfortunately doesn't have nice solutions at all

round geyser
#

I agree

#

It’s 0.54138

#

Or (-5 + sqrt(37))/2

round geyser
#

I like this kind of question

#

a=22.41(b+c)
b=0.83c

#

ā€œWhat percent of b is aā€ can be a is what percent of b

#

Is that right

echo sinew
#

Yes

echo sinew
#

Who tf did come up with that huge percentage lol

round geyser
#

So, my idea is sub in 0.83c
a=22.42((0.83c)+c)

#

a=22.42(1.83c)

#

Solving for c in b=0.83c which is c=0.83/b

#

a=(22.42 x 1.83 x 0.83)/b

round geyser
chilly arrow
#

Trivial if you have a calculator but would be annoying to do manually

prime bear
#

Hi I’m a bit confused on how to take the derivative of this function (don’t know where to start) (12)

echo sinew
#

Do you agree it's a fraction, don't you? Therefore, you'll need to apply the formula for the derivative of a quotient

prime bear
#

yes

#

Do we use the power rule

#

To take the derivative of the numerator

echo sinew
#

Yup (together with chain rule)

prime bear
#

Ohh chain as well

#

Ok thanks

undone pumice
prime bear
undone pumice
prime bear
undone pumice
#

np

dry verge
fossil kindle
#

i think

#

i js did t(x) = sqrt((x³-1)/(4x²+4x+1))

#

and then f(x) = sqrt(x) and g(x) = (x³-1)/(4x²+4x+1) and t(x) = f(g(x))

#

prolly overkill tho

fierce remnant
#

I have 8 weeks to learn precalc

#

how tough will it be?

undone pumice
#

how are your algebra and trig foundations

fierce remnant
#

I got 3.0 on algebra

undone pumice
#

3.0?

fierce remnant
#

yup for the smester but I slacked on the final

undone pumice
#

wait

#

3.0 out of like

#

what

fierce remnant
#

3.0 or B-

undone pumice
#

OH like gpa wise got it

#

uhhh

#

in my experience (im in precalc rn) precalc is just alg2 stuff with some new concepts, plus trig (unit circle and reciprocal) and that stuff, plus limits maybe

fierce remnant
#

I am older student and I want to get through this to get further in my CIS degree

undone pumice
#

I see

fierce remnant
#

I just bought precalc by sullivan

undone pumice
#

Ah

lilac verge
haughty crown
fierce remnant
#

Lord fang believes in me

undone pumice
#

i did it in integrated 3 at my school

#

well not at mu school in middle school but ye

#

so lwk it wasn't that bad cus it was basically js review for me

#

but the kids who skipped int3 and were taking this class as sophmores lowk struggled with unit circle

lost rivet
#

How do u find the max of s

#

I’ve found dt/ds

astral apex
#

I think you have an exponent 1/2 in your derivative where you meant to have a -1/2

#

The second exponent 1/2 in the numerator

lost rivet
#

Wait oh yes

#

Y is my denominator 1 now bro

#

N I hv the (2t+100)^-1 still

fickle gulch
#

Hello

tough flare
obsidian monolithBOT
#

Ujjawal Gupta

tame shard
#

Thats is just adding n to itself n times

tough flare
fossil kindle
tame shard
tough flare
tame shard
round ermine
# lost rivet

why did you re-add the ^(1/2) to the denominator on the second step there

gaunt moat
#

n*n times

sharp geyser
#

Does anyone recommend any good videos that clearly and effectively explain the unit circle and how to apply it? Im having difficulty understanding it and using it for my school work šŸ˜“

sharp geyser
hushed sphinx
#

Can you explain more specifically what confuses you? The concept of a circle centered on (0,0) with radius 1 shouldn't take a video to explain.

red jewel
sharp geyser
#

Yeah, nah not that that’s obviously easy, but like the degrees given in the circle and the fractions with pi and the fractions on the outside

hushed sphinx
#

In some educational contexts, however, "unit circle" refers not just to the circle, but to an excessively complex diagram full of coordinates and angles for a dozen+ particular points.

sharp geyser
#

Im sorry if i can’t really explain well šŸ˜“

red jewel
#

No its ok

sharp geyser
red jewel
#

Ļ€ = 180°