#precalculus

1 messages ยท Page 195 of 1

pale bison
#

but, you square the number first, which will turn it positive

willow bear
#

@pale bison no

wraith idol
trim fable
#

do u get what

willow bear
#

what you wrote on the very left is $x^{\sqrt{2}}$

trim fable
#

im thinking

obsidian monolithBOT
willow bear
#

if $x \geq 0$, then $\sqrt{x^2} = x$.

if $x < 0$, then $\sqrt{x^2} = -x$.

obsidian monolithBOT
willow bear
#

@trim fable

trim fable
#

yes?

#

no but

#

u square the number

#

oh..

willow bear
#

i wrote everything.

trim fable
#

so -5^2
=-25

#

so its not (-5)^2
=25

willow bear
#

what?

#

what does that have to do with anything?

trim fable
#

brackets matter

#

๐Ÿ˜›

#

uh

#

that

willow bear
#

and?

trim fable
#

coz i was thinking

#

so its not (-5)^2
=25

#

this at first so

willow bear
#

if $x \geq 0$, then $\sqrt{x^2} = x$.

if $x < 0$, then $\sqrt{x^2} = -x$.

this requires no further comments.

trim fable
#

every number would be

obsidian monolithBOT
trim fable
#

positive

#

alright

willow bear
#

$\sqrt{x^2} = |x|$ literally by definition.

obsidian monolithBOT
willow bear
#

do you understand this or not.

trim fable
#

not anymore

#

tbh

#

is that a rule

#

or something coz

willow bear
#

no

trim fable
#

ill keep that in mind

#

LOL

willow bear
#

i literally just explained it

trim fable
#

ok

#

oh

willow bear
#

ok

#

look

#

stop typing

trim fable
#

ok

willow bear
#

I SAID STOP TYPING

#

ok

trim fable
#

ok..

willow bear
#

if $x \geq 0$, then $\sqrt{x^2} = x$.

obsidian monolithBOT
willow bear
#

do you understand this or not

trim fable
#

yes

#

but question

#

if the number is -5 for example

willow bear
#

is it true that $-5 \geq 0$?

trim fable
#

its not (-5)^2?

obsidian monolithBOT
trim fable
#

no

willow bear
#

no, it is not true that $-5 \geq 0$.

obsidian monolithBOT
trim fable
#

lol

willow bear
#

if $x < 0$, then $\sqrt{x^2} = -x$.

obsidian monolithBOT
willow bear
#

do you understand this or not

trim fable
#

yes?

#

but u wont answer my question

#

u wont square the negative with the number

#

just the number?

willow bear
#

your question makes no sense

trim fable
#

so its technically - (5)^2 = -25 not (-5)^2=25?

willow bear
#

if the number is -5 for example
its not (-5)^2?
what's it?

#

what's "it"?

#

what's "it"?

#

what's "it"?

trim fable
#

the answer

willow bear
#

what answer

trim fable
#

its not 25?

#

for that

#

expression

willow bear
#

YOU'RE NOT MAKING ANY SENSE.

trim fable
#

of rip

willow bear
#

WHAT EXPRESSION.

trim fable
#

am I not?

#

@pale bison am I not making sense?

uncut mulch
#

x^2 when x= -5 apparently

willow bear
#

IF $x = -5$, THEN $x^2 = (-5)^2$.

obsidian monolithBOT
trim fable
#

ooof..

#

but ur saying the answer will be -

#

for negative numbers

willow bear
#

okay so

#

look

trim fable
#

but what i was saying was

willow bear
#

no stop

trim fable
#

ok

willow bear
#

there are exactly two real numbers which when squared give x^2

#

x and -x

#

do you understand this or not

trim fable
#

yes

#

x could be + or -

willow bear
#

no, stop.

#

i'm not done.

trim fable
#

oh ok

willow bear
#

for any given value of x, sqrt(x^2) will by definition have to be one of these values.

#

it will be precisely the one of these values that is positive.

#

do you understand this or not.

trim fable
#

yes

willow bear
#

okay.

trim fable
#

what im saying is it will ALWAYS BE + ?

willow bear
#

I'M NOT DONE YET.

trim fable
#

which is why its absolute

#

oh rip

#

ok calm down

#

relax

willow bear
#

when x is positive, -x is negative, and therefore sqrt(x^2) = x.

#

do you understand this or not.

trim fable
#

yes

#

yessssss

willow bear
#

when x is negative, -x is positive, and therefore sqrt(x^2) = -x.

trim fable
#

no

#

thats what im arguing about LOL

willow bear
#

when x is negative, -x is positive.

trim fable
#

well what i was questioning actually

willow bear
#

do you disagree with this?

trim fable
#

(-x)^2 is positive

willow bear
#

when x is negative, -x is positive. do you disagree with this?

#

i am expecting one of two answers:
"yes, i disagree with this" or "no, i agree with this"

trim fable
#

no

#

?

#

i agree?

#

u mean the final

#

answer

#

when u say -x right?

#

like after u square?

willow bear
#

for any given value of x, sqrt(x^2) will by definition have to be one of x and -x.
it will be precisely the one of these values that is positive.
when x is negative, -x is positive.
therefore, when x is negative, sqrt(x^2) = -x.

trim fable
#

nooooo

#

im sooooo

#

confuseddd

#

ok hold on

willow bear
#

what part of what i just wrote is confusing?

trim fable
#

ok so

#

what we are saying is

willow bear
#

i was under the impression that the entire argument was laid out crystal clear

trim fable
#

alright so

willow bear
#

and that i "meant" exactly what i said

trim fable
#

listen

#

closely ๐Ÿ˜›

willow bear
#

NO THAT WAS THE FUCKING CONCLUSION

#

GODDAMNIT

#

YOU KEEP SKIPPING AHEAD

undone pawn
#

lmao

trim fable
#

Listennnnnnnnnnnnnnnnnnnnn

#

LOL

#

this is related

#

ok this is a great question

willow bear
#

what the fuck do you have to say now

trim fable
#

oh ill tell u

#

ok so

#

LET -5 = X ok there

#

so

#

sqrt(x^2)

#

sqrt(-5^2)

uncut mulch
#

no

trim fable
#

Ok we are on this step

#

huh

willow bear
#

no

trim fable
#

my question was

#

HUH

uncut mulch
#

you aren't squaring x there

undone pawn
#

i shall also join in

#

no

willow bear
#

if x = -5, then x^2 is NOT -5^2

trim fable
#

Its

#

(-5)^2

undone pawn
#

(-5)^2

willow bear
#

because ORDER OF OPERATIONS is a thing no matter how much you wish to forget about it

trim fable
#

YES

#

OK THERE

#

THATTTT WASSSS MYYY QUESTION YAY

#

ok

#

sowhat i was saying from

wraith idol
trim fable
#

the very start was rightttt

#

rightttttt?

#

coz u were saying

#

that

willow bear
#

what you were saying made very little sense if indeed it made any sense at all.

trim fable
#

ok

#

u know

#

u complicated things by saying this:

#

oh wait..

willow bear
#

no

trim fable
#

were u

willow bear
#

i did not

trim fable
#

talking about

#

The final answer????

#

ohhhhhh ripppppppppp

#

omggggggggg

#

what was i thinkinggggggggggg

#

i thought u meant

undone pawn
#

bruh

willow bear
#

if by "the final answer" you mean "the value of sqrt(x^2)"

undone pawn
#

that was basically expanding the |x|

trim fable
#

OMGG

willow bear
#

THEN YES OF FUCKING COURSE THAT IS WHAT I WAS TALKING ABOUT

trim fable
#

IM SO STUPID

#

no wait

#

what

undone pawn
#

wot m8

trim fable
#

the x should be positive

#

for both cases

grizzled orchid
trim fable
#

coz ur squaring itttt

undone pawn
#

what the fuck are you saying

willow bear
#

what

trim fable
#

so i started questioning u

grizzled orchid
#

hi ann

uncut mulch
#

whut?

grizzled orchid
#

are we in hell again today

willow bear
#

BRUH

#

yes

trim fable
#

YES

#

its always positive which is what i saiddd

#

which is whyyy

uncut mulch
#

the x is clearly negative in the second case as stated by "x < 0"

trim fable
#

its absolute wow

undone pawn
#

you mean the square root?

willow bear
#

no LOOK

undone pawn
#

yes that is always positive

trim fable
#

YES

willow bear
#

JUST BECAUSE A MINUS SIGN APPEARS IN FRONT OF A VARIABLE

undone pawn
#

^

#

but if x is negative then -x is positive

willow bear
#

DOESN'T MEAN THE VARIABLE ITSELF "IS NEGATIVE"

trim fable
#

i thought he meant after squaring u got a - coz i thought he was doing

undone pawn
#

if x is positive, then +x is positive

trim fable
#

-5^2

#

not

willow bear
#

who's he

trim fable
#

(-5)^2

#

u

undone pawn
#

oh no

#

F

willow bear
#

i'm a she

trim fable
#

oh rip sorry

#

LOL

#

im a she too

#

๐Ÿ˜›

willow bear
#

k

undone pawn
#

aight

wraith idol
#

Damn

trim fable
#

LOL GIRL FIGHT OVER MATH

#

YES

#

did I win?

#

LOL

#

lol honestly tho

undone pawn
#

okaaay

willow bear
trim fable
#

I was

#

right but

fluid shore
#

Stop

#

This is not a productive conversation.

undone pawn
#

no u

trim fable
#

no u

undone pawn
#

ur not a productive conversation abhi

#

get rekt

trim fable
#

๐Ÿ˜ฎ

#

oof..

#

well @willow bear sorry

fluid shore
#

Why?

trim fable
#

u were right but i was too

fluid shore
#

You have nothing to apologize for

willow bear
#

hhh

trim fable
#

i just confused what u said and thought u were

#

talking about

fluid shore
#

Just learn as much as possible and move on.

trim fable
#

the final answer when u said -x

#

im dumb

#

lol

willow bear
#

i feel like i lost a few thousand think pan cells from this

trim fable
#

oh no..

#

IM SORRY

#

gives u my brain cells

#

tho idk if

#

u want them

#

they are pretty useless it wont

#

make a difference

#

lol

willow bear
#

it's ok you can keep them

fluid shore
#

Ann, you worked yourself up over something like this.

trim fable
#

yes she did

#

well i feel like

#

i committed a crime

#

do I cry

fluid shore
#

Anyways, Star, just try to understand what Flynn and Ann were telling you before

trim fable
#

i feel bad lol it turned into a math war

#

i did

uncut mulch
#

are there still parts you aren't sure about?

trim fable
#

i just thought they meant something else

undone pawn
#

ohh

trim fable
#

tho the final answer in the end was

#

agreeable

#

i guess

#

ye so

#

are u all mad at me ;-;

fluid shore
#

It's okay. There was no reason for them to work themselves up like that.

trim fable
#

sorry guys

fluid shore
#

There's no reason to be mad at you.

trim fable
#

im sorry

#

:C

#

DO I GO TO MATH JAIL

fluid shore
#

Like what ramonov asked, is there anything you're unsure about?

trim fable
#

take me awayyyyy OFFICERS

#

๐Ÿš“

#

I feel RUDE TAKE ME AWAY

slim lintel
#

jesus christ

trim fable
#

uh

#

hi?

#

๐Ÿ˜›

#

im good @fluid shore

#

thanks people

fluid shore
#

Alright.

trim fable
#

uh

#

and again

#

im very sorry

#

tho i guess we practiced our debating skills

#

YAY?

fluid shore
#

There's no reason for ANYONE here to get irritated just because you're asking questions.

trim fable
#

there u got the english u wanted @fluid shore

uncut mulch
#

just don't use freshman's dream again

slim lintel
#

you can thank everyone by stopping spamming please

#

if you have nothing math related

trim fable
#

what do u mean @uncut mulch

#

this is math related

#

math related emotions

#

EVERYONE

#

there lol

uncut mulch
#

earlier you implied that the sqrt was linear

trim fable
#

ME?

uncut mulch
#

yes

trim fable
#

oh rip when

uncut mulch
#

sqrt(x^2 - 2) โ†’ x - sqrt(2)

trim fable
#

๐Ÿ˜…

#

well that didn't lead to

#

that conversation so

#

whats freshmans dream tho

fluid shore
#

Idk lol, it's a term that some of them use for some incorrect stuff

#

Anywyas, if you're stuck on something, just ask questions.

trim fable
#

aww thanksss

#

wait so they weren't equal LOL

#

right?

#

x != |x|

#

right

#

๐Ÿ˜›

willow bear
#

in general yes this is false

trim fable
#

ok

willow bear
#

freshman's dream is sth different

trim fable
#

sth?

uncut mulch
#

something

trim fable
#

oh

fluid shore
#

,w graph y = x

pale bison
#

how many freshman's dream are there,
are there an undergrad's dream?

obsidian monolithBOT
willow bear
#

freshman's dream is $(x+y)^p \overset{?!}= x^p + y^p$

fluid shore
#

,w graph y = abs x

obsidian monolithBOT
trim fable
#

huh

undone pawn
#

what

#

why

#

so many messages

fluid shore
#

Notice the difference in the two graphs?

#

For x and |x|?

trim fable
#

yes

#

LOL

#

im dumb oops

#

i should know that

#

maybe i should think before

#

i talk

fluid shore
#

Just wanted to give you a visual image of it.

trim fable
#

yes

willow bear
#

freshman's dream is $(x+y)^p \overset{?!}= x^p + y^p$, for $p \neq 1$. most often encountered with $p = 2, 3, \frac12, -1$.

trim fable
#

what

fluid shore
#

Well, that's usually a good thing to do but making mistakes is absolutely fine.

obsidian monolithBOT
trim fable
#

im in grade 12 and im making dumb mistakes like that

#

thats honestly pretty sad

#

tho i am good at it i just do random stuff at timed

fluid shore
#

Well, then, try not to make such mistakes in the future

trim fable
#

i invent new ones ๐Ÿ˜…

#

lol

fluid shore
#

If you want to learn this stuff in greater detail, i'd suggest using something like brilliant.org

trim fable
#

ok

fluid shore
#

Use the wikis there to learn the material and solve problems there as well.

trim fable
#

ok

undone pawn
#

abhijeet is the brand ambassador for brilliant

trim fable
#

๐Ÿ˜ฎ

fluid shore
#

Well, I think it's a fantastic resource.

undone pawn
#

thats exactly what a brand ambassador would say

#

co incidence?

#

i think not

pale bison
#

did someone mentioned brillian.org, our sponsor for todays video

undone pawn
#

^

willow bear
#

ok so like. yeah

#

freshman's dream

pale bison
#

honestly, i'm like iffy on what brillian's doing in terms of building their own wiki page

willow bear
#

an entire class of fuckups

pale bison
#

just doesn't seem right to copy off wikipidia

undone pawn
#

ann how could you interrupt the part where we thank our sponsors

fluid shore
#

Oh they don't, from what i've used anyways. The wikis are made mostly by olympiad students who've learned the material from other sources

pale bison
#

use code im total sellout to get 10% off your first month of purchase

fluid shore
#

Now, it has branched away from olympiad material

uncut mulch
#

if they're sponsoring us, they're not doing a very good job

native sequoia
#

just in case Wikipedia goes down, but that will never happen because you have donated catGun

undone pawn
#

true

#

lmao

#

well we could technically download all of wikipedia onto an external drive at this point

fluid shore
#

I've contributed to their physics wikis before but that was at a time when my understanding of physics was very limited.

pale bison
#

there's a chinese wiki called ็™พๅบฆ็™พ็ง‘

fluid shore
#

I just don't understand why this devolved into such a massive fight. I don't even understand how it got linked in chill.

#

But whatever

pale bison
#

what fight?

undone pawn
#

what fight

willow bear
#

baidu wiki?

fluid shore
willow bear
#

there's a chinese wiki called ็™พๅบฆ็™พ็ง‘

#

or uh

pale bison
#

well yeah i merely mentioned it

willow bear
#

baidu-pedia i guess

pale bison
#

i don't see a problem

willow bear
#

็™พ is like, the hanzi for ๐Ÿ’ฏ or sth

pale bison
#

i'm suggesting that in the very unlikely of wikipidia going down, there's a chinese one

fluid shore
#

20 years living in singapore and i still can't speak chinese or even read it

pale bison
#

it means one hundred

fluid shore
#

I've heard it's a pain in the ass to learn

native sequoia
#

hundred

undone pawn
#

mandarin

#

i learnt that for a few years in singapore i think

#

i remember nothing

pale bison
#

i agree

willow bear
pale bison
#

TIL

native sequoia
#

I thought it was 100 horizontal lines

pale bison
#

how do you explain that ็™ฝ means "white" then?

willow bear
#

idk

#

white=99 i guess

fluid shore
pale bison
#

lmao

wraith idol
#

Bruh

#

@pale bison that's not white, that word means 100 in chinese

viscid thistle
#

what

pale bison
#

็™พ means 100
็™ฝ means white

fluid shore
pale bison
#

chill... i'm just responding to his message

vernal rapids
#

$\dv{็™ฝ} $

obsidian monolithBOT
viscid thistle
#

้›จ is the best looking character imho

native sequoia
#

็ˆจ

sour quiver
#

่ตข

viscid thistle
#

ใŠๆฏใฏๅคชใฃใฆใ„ใพใ™

fast tinsel
#

Could anyone explain how to solve so the variables become the above?

#

I basically put them both on the same fraction, multiplying A with xยฒ+x+1 and Bx+c with x-1

fluid shore
#

Yes

#

Then?

#

What do you do after that?

fast tinsel
#

Then I take out the X's, everything in the brackets of Xยฒ(...) should be 0

#

same for X(...)

#

and the rest is equal to 1

#

But that doesn't work at all

fluid shore
#

In other words, we compare coefficients and get A, B & C

willow bear
#

But that doesn't work at all

#

wdym

#

you're on the right track so far, based on what you've said

#

what exactly does not work

fast tinsel
#

I end up with xยฒ(A+b) + x(-A+B+C) + C +1

#

A+B = 0

willow bear
#

do you?

#

hang on

fast tinsel
#

-A+B+C = 0

willow bear
#

,w expand a(x^2 + x + 1) + (bx+c)(x-1)

fast tinsel
#

oh

obsidian monolithBOT
willow bear
#

-.-

#

thank you WA very helpful /s

fast tinsel
#

xd

#

oh no I made a mistake

willow bear
#

$ a(x^2 + x + 1) + (bx+c)(x-1) = ax^2 + ax + a + bx^2 - bx + cx - c$

obsidian monolithBOT
willow bear
#

$= (a+b)x^2 + (a-b+c)x + (a - c)$

obsidian monolithBOT
fast tinsel
#

I forgot the A in the end indeed

#

yikes

#

Thanks a bunch!!

fast tinsel
#

General question out of curiosity:
If I take the derivative of the integral of some function f(x), then I would get f(x), right?

But if this integral is definite, with x going from a to b, is the derivative of the integral of f(x) equal to f(b)-f(a)?

viscid thistle
#

it would be easier for you to check this yourself than to ask

#

but also think about what do you really mean when you as kthat question

#

is it coherent?

fast tinsel
#

I'm not sure what you mean by that, English isn't my first language

frozen needle
#

Well first, functions that look like
$$x\mapsto\int_a^xf(t)\dd t$$
aren't always differentiable everywhere, so even your first question should be answered negatively I suppose

obsidian monolithBOT
fast tinsel
#

Oh yeah, true

#

Perhaps in the example of the derivative of the definite integral of (cos(xยฒ)) with x going from a->b

frozen needle
#

you can even have differentiable functions that look like
$$x\mapsto\int_a^xf(t)\dd t$$
but which derivative isn't equal to $f$

obsidian monolithBOT
fast tinsel
#

I see

#

Wait I'm not wording my question right

frozen needle
#

for your second question, you're asking about the derivative of the number $\int_a^bf(t)\dd t$
\ \
if you identify the number with the constant function, then its derivative is $0$

obsidian monolithBOT
fast tinsel
#

Right, that makes sense

#

If I could ask one more thing, say we introduce a second variable, like so:
d(integral a->x of cos(tยฒ)dt)/dx

#

If that's readable

#

What would this give us?

#

I can't really calculate the integral first, that's my biggest issue

#

Thanks for the clear explanation by the way

frozen needle
#

there's a theorem

#

basically with continuous functions everything works fine

#

if $f$ is continuous then $F:x\mapsto\int_a^xf$ is differentiable and $F'=f$

obsidian monolithBOT
fast tinsel
#

Oh right, that would work with what you said earlier (my second question)

#

Perfect, very much appreciated

frozen needle
#

You're welcome

odd helm
#

For this problem

valid violet
#

@odd helm I dont see any equation

#

"50 dollars per piece" means you need to multiply the number of pieces by 50

rigid sun
#

i think he's trying to describe a profit function

#

if the starting price is 50, and you are projected to sell 4,500 units, then you're equation looks right

#

im no sure what they are doing

odd helm
#

It is 50 dollar per piece= 4500 items sold

#

Every dollar increase means 5 less items sold

rigid sun
#

exactly

#

so urs is right

odd helm
#

Oh

rigid sun
#

im not sure what they are doing tho

#

im really lost on what they are doing

#

oh i got it

#

they are doing it by actual price

#

not increase like you did

#

yeah same thing

odd helm
#

Alright

hallow flicker
#

And whatโ€™s the use of a dx in the end of a integral

#

Ok so if I solve both those equestions whatโ€™s the answer for both

uncut mulch
#

how much integration have you done?

hallow flicker
#

Like none

uncut mulch
#

then the answers we give will probs be meaningless to you

hallow flicker
#

Is it possible to answer the second one

undone pawn
#

hm

#

yes

hallow flicker
#

So whatโ€™s the answer

uncut mulch
#

how much calculus have you done?

hallow flicker
#

Fuck off

#

Ok this is true right?

#

Well I have to add the d theta in the end

#

But this means that the d whatever is the same as taking the derivative

#

Yo someone answer

undone pawn
#

$\int \sin\theta \ d\sin\theta = \frac{\sin^2\theta}{2} + c$

obsidian monolithBOT
undone pawn
#

$\int \sin\theta \ d\theta = -\cos\theta + c$

obsidian monolithBOT
undone pawn
#

$dy = \bigg(\frac{dy} {dx}\bigg) dx $

obsidian monolithBOT
hallow flicker
#

Ok great

#

So why do you take the derivative

#

Like here

uncut mulch
#

that's not correct though

hallow flicker
#

It is

#

This right

undone pawn
#

I think there's a - missing too

uncut mulch
#

^

hallow flicker
#

Yea same thing

#

But like why do you take the derivative

uncut mulch
#

because the integrand isn't in terms of the thing you're integrating with respect to,
and you'll need to do some maniuplation

hallow flicker
#

Why canโ€™t I take the derivative of x here

uncut mulch
#

i mean you could try, but you'll still be left with dx

undone pawn
#

it just depends on whether it simplifies your problem or not

#

in case of sinx d(sinx) it actually is easier to evaluate

uncut mulch
#

i reworded what i posted earlier

undone pawn
#

you can play around with the d(..) in many ways

#

that's basically the whole u-sub thing

uncut mulch
#

the integrand here x^2 is in terms of x so manipulation of the differential isn't needed

undone pawn
#

you could if you wanted to

#

but it doesn't help

hallow flicker
#

Cool that was helpful

winter isle
#

@hallow flicker you're doing integrals in precalc?

viscid thistle
#

gnarly scope creep

hallow flicker
#

Iโ€™m doing ur mom dude

fluid shore
#

Rekt

viscid thistle
#

$\mathbb{R} e^{k} \dagger$

obsidian monolithBOT
native sequoia
#

OOOOOOOOOOOOOOO

fluid shore
#

Ur mom jokes are the best ones tbh

#

Applicable in nearly every situation

pale bison
#

ur mom is applicable in nearly every situation

fluid shore
#

Oh shit rekt

radiant night
uncut mulch
#

do you know your unit circle?

willow bear
#

what's giving you trouble here? @radiant night

radiant night
#

Well I know how to use the unit circle, but one wasnt provided since its sub work.

#

And I need the theta= aswell, since it's been a while since I've done that,

willow bear
#

Well I know how to use the unit circle, but one wasnt provided since its sub work.
you're supposed to be able to reproduce it from scratch

radiant night
#

Well, we've only learned it a couple times, and I dont have the greatest memory.

viscid thistle
#

memorize it, or memorize the special right triangles

uncut mulch
#

^ do you at least understand the first quadrant

viscid thistle
#

you only need to memorize the first quadrant

#

the rest is the same but just use sin cos rules in different quadrants

#

A S T C

regal nest
#

I dont have the greatest memory
You have google for that

viscid thistle
#

^^

#

but just memorize it, you'll need it on tests and stuff

languid crane
#

||luckily we have a formula book for all formulas in hs math||

willow bear
#

i'd say don't memorize but i don't have enough energy rn

neat gate
#

The basic trig values have easy to remember patterns. (root 1)/2, (root 2)/2 and (root 3)/2 for (co)-sines. And (root 3)^1 /3, (root 3)^2 /3 and (root 3)^3 /3 for tan.

rigid beacon
#

Well you only need to memorize first quadrant

#

And then if you can draw the triangles on the axis

#

You're good

#

Because the unit circle lies on the xy plane

#

So

#

If the triangle is in the 2nd quadrant

#

You know that the cosine (which lies is the x-axis) is negative because in the 2nd quadrant x is negative

#

Cause it goes to the left, and in the plane we define left of zero as negative

trim fable
#

hi people how would u do c ii

fluid shore
#

What do you think?

trim fable
#

1/x^2-1

fluid shore
#

No, thatโ€™s not the answer to my question.

trim fable
#

oh

fluid shore
#

My question was: what do you think is the approach to be taken?

trim fable
#

oh

#

so take 1/x^2-1 and plug in f into x

#

which gives u 1/(1/x)^2-1

#

and then 1/1/x^2-1

fluid shore
#

Why?

#

Why do you just plug it in?

trim fable
#

coz its g composite of f

#

which means g(f(x))

#

so u plug and solve

fluid shore
#

Since itโ€™s g(f(x)), shouldnโ€™t you be plugging in f(x) into g(x)?

trim fable
#

thats what i did?

fluid shore
#

What you did was f(g(x))

trim fable
#

x^2-1

#

no?

#

1/x^2-1 was g(x) and then i plugged in 1/x which was f(x)

fluid shore
#

Oh wait nvm, i misinterpreted your working

trim fable
#

oh sorry

willow bear
#

1/x^2-1

#

this reads as $\frac{1}{x^2} - 1$, not as $\frac{1}{x^2 - 1}$

obsidian monolithBOT
fluid shore
#

Yea yea lmao

trim fable
#

oh oops

fluid shore
#

Use latex to type this stuff out, star

trim fable
#

idk how to use it

#

lol

#

sorry ye i should use that

#

so i dont confuse people

fluid shore
#

$\frac{1}{(\frac{1}{x})^2 - 1}$

obsidian monolithBOT
fluid shore
#

Thatโ€™s what you were going for?

trim fable
#

yeah

fluid shore
#

Aight, then simplify

trim fable
#

1/ (1/x^2)-1

#

sorry idk how to use that bot

#

,help

obsidian monolithBOT
#

A brief description and guide on how to use me was sent to your DMs! Please use ,list to see a list of all my commands, and ,help cmd to get detailed help on a command!

trim fable
#

well ill just tell u my final answers

#

i guess

#

those

fluid shore
#

Uhhhhhhhhhhh

#

c ii looks wrong

#

Itโ€™s late here and iโ€™m tired but it just seems wrong, given what you had earlier

trim fable
#

oh

#

rip

#

can someone else tell me if i made a mistake?

willow bear
#

yes you did

trim fable
#

oh

#

what was it supposed to be

#

ci was right tho?

#

@willow bear

willow bear
#

yes c i is right

trim fable
#

what was the answer for cii?

#

then?

fluid shore
#

$\frac{1}{(\frac{1}{x})^2 - 1}$

obsidian monolithBOT
fluid shore
#

Simplify this properly

trim fable
#

ok

languid crane
#

The feeling when u think ci and cii are related and some higher math

#

Tired, perhaps

viscid thistle
#

Can I ask my questions

serene heath
#

no

#

@viscid thistle JustAsk

viscid thistle
#

Isk how to do 5 - 6 - 7 and 8 ๐Ÿ˜ฆ

#

Iโ€™m done the first 4

trim fable
#

I cant even read those questions @viscid thistle

#

sorry

dull ice
#

Zoom in lmao

viscid thistle
#

I can provide some insights on question 6

viscid thistle
#

For question 6, consider the periodicity of the trig functions.

#

And compare it with the average rate of change

#

Sin, cos and tan will have an average rate of change equal to zero

#

Now consider the inverse trig functions

#

arcsin and arccos are not defined when given an input 2pi so discard those

#

arctan(2pi) - arctan(0) = some number greater than zero (calculator)

#

So discard arctan

#

โ€”

#

Now youโ€™ll need to test the hyperbolic function and their inverse

#

Which Iโ€™m too lazy to do

vale basin
#

Fig1 striped surface?

#

Can someone help mr

gusty halo
#

,rotate 90

#

,rotate 180

obsidian monolithBOT
silk crystal
#

How do you make a rational function with an extraneous solution?

harsh cipher
#

Hi

#

is that a typo in the second line in the answer section

#

question says csc > theta

willow bear
#

no

harsh cipher
#

then sec theta is positive?

willow bear
#

the question says csc(ฮธ) > 0 not "csc > ฮธ"

harsh cipher
#

yes i meant that

#

but in the answer section is that sec ฮธ is positive?

#

that's a typo i think...

willow bear
#

anyway yeah it's a typo and they meant csc and not sec

harsh cipher
#

okay thank you Ann

#

Happy new year

willow bear
#

it's been 4 days already lmao

harsh cipher
#

hahahaha

dull ice
#

Is that

#

SVHS website

#

๐Ÿค” ๐Ÿ‘€

vale basin
#

How can i solve log9

#

ยฑ

#

With using defferentials

languid crane
#

Idk what log9ยฑ with โ€defferentialsโ€ means

#

And how is that precalc

vale basin
#

I didnt know where to ask ๐Ÿ˜…

languid crane
#

Explain

vale basin
#

We need to solve log 9 approximately

languid crane
#

Base 10 log

#

Right

fluid shore
#

no u

#

prank

languid crane
#

?!?

vale basin
#

Yes base 10 log

vale basin
#

Nvm i got it

ebon raptor
#

hey guys! i have a math problem i have been stumped on for an hour

fluid shore
ebon raptor
#

so it shows me the answer is -7/-3

#

but i cannot get to that answer no matter how hard i try lol

#

ill send my "work" in a second

#

does it show how to get the steps

pale bison
#

pearson socks?

timber plinth
#

,w vertex of 3x^2+8x+3

obsidian monolithBOT
timber plinth
#

so, have you ever done finding the vertex of a parabola before?

ebon raptor
#

yes i have

#

i am having trouble with plugging the fraction in the problem

timber plinth
#

what are you doing

#

are you not squaring it right?

pale bison
#

show us your step by step work

timber plinth
#

^

ebon raptor
timber plinth
#

what

#

what is that jump

#

^

ebon raptor
#

lol

#

its been along time

timber plinth
#

that 16/3 is negative

fluid shore
#

You should really leave a blank line between each statement in your working.

timber plinth
#

nah I don't do that

#

inefficient

ebon raptor
#

ah i would subtract the 16/3 from 3

fluid shore
#

^What you do or don't isn't the point. It's neat to do it that way.

timber plinth
#

then again I write stuff like $\forall a \exists b \phi_a(b)\implies \psi(c)\vdash \forall a \eta(a)$

obsidian monolithBOT
timber plinth
#

also yes goon

#

(note: ignore the thing I wrote above, it's a meaningless example of why you shouldn't write like me)

ebon raptor
#

hold on dont answer, lemme think a sec

#

(9/3)-(16/3)=(-7/3)

timber plinth
#

that looks a lot like the right answer

ebon raptor
#

haha awesome i was improperly messing with the faction and whole number

#

thank you! glad i found this discord

viral imp
#

$y=2\arctan{\frac{x+1}{3}}$

obsidian monolithBOT
viral imp
#

$x=3\tan{\frac{y}{2}}-1$

obsidian monolithBOT
viral imp
#

I had to find the inverse of the first function, which is the second one, no problem about that. The thing is I have to determine the domain of the inverse function as well

#

given that there's a tangent I would be tempted to say that all values of y are valid except -pi/2 and pi/2

#

however it seems that the correct domain is $y\neq\pi+2k\pi$

obsidian monolithBOT
viral imp
#

can anyone explain this?

last compass
#

Well when does y/2 take a value that is a integer multiple of pi/2

willow bear
#

an ODD integer multiple of pi/2

desert socket
#

Iโ€™m having some sort of brain fart. How is (1+x^2)^1/2 * (1+x^2) = (1+x^2)^3/2. Where is the ^2 exponent thatโ€™s being added coming from.

#

Or is it (1+x^2)^2+ ^1/2.

#

That might be it. Nvm.

rigid beacon
#

@desert socket (1+x^2) = (1+x^2)^1

#

and then it's exponent rules

#

a^b * a^c = a^(b+c)

desert socket
#

I got it. Thanks!

proud jetty
#

How would I go about doing that

ebon raptor
#

lol i have someone making me second guess myself

#

the answer to that should be 3 right

proud jetty
#

yea

ebon raptor
#

ok thats what i was thinking lol caught it on a peer review and had another friend explaining some crazy shit making me second guess myself

#

is that the whole question that u posted @proud jetty

proud jetty
#

yes

#

unit is permutations and combinations. every letter have a different answer, u gotta solve for it.(not a multiple choice question)

slate tree
#

how do i do "how many code words of any length can be spelled out using gmae timles of five different litters ( including single lettered words)

#

also how do you do

#

expansioin of polynomials byeond binomial

#

can anyone help me please

willow bear
#

uh

undone pawn
#

wtf is gmae timles

willow bear
#

^

slate tree
#

game tiles

#

sorry typo

undone pawn
#

oh ok

#

five different letters

slate tree
#

yeah

undone pawn
#

well I assume the "words" don't have to make sense

slate tree
#

yeah i dont think so

undone pawn
#

just random permutations of the letters

#

what's your difficulty then

#

minimum length is 1, max is 5, take each case and figure the number of possible words

slate tree
#

oh i did that but looking back i realized what i did wrong

#

i used the wrong amount

#

coluld you also help explain how i do expansion of a polynomial that is greator than a bionomial

undone pawn
#

what does that even mean

slate tree
#

so binoimal expansion is when its like this (x+1) (y+1)

#

but im talking about something like a tri nomial

#

so with three of those

undone pawn
#

binomial expands stuff like (a+b)^n

#

trinomial would be like (a+b+c)^n

slate tree
#

yeah but how would i distribute through with a short cut method

undone pawn
slate tree
#

thanks

undone pawn
#

not sure if that's what you're asking for, but check it out anyways

#

we derived this in hs, cool stuff

slate tree
#

cool thanks

#

i think i also realized that for my school we used something called lines and stars method

#

its k9inda weird but it works

undone pawn
#

yeah I remember that one

viscid thistle
#

How would I find the domain of

#

sqrt1+a^2

valid violet
#

@viscid thistle PARENS

serene heath
#

i mean

#

if it was just 1+a^2 then the sqrt is extra

pale bison
#

it's g o o d p r a c t i c e tho

willow bear
#

paku dropped a question here and went offline presumably to wait until the answer is handed to them

karmic wave
#

hopefully they went to find a book that explains how parentheses work

summer monolith
pale bison
#

yes

summer monolith
#

3 misprints on one page. They've gotta be shitting right into my soul.

languid radish
#

For computers, what base is the log function set to by default?

willow bear
#

wdym by "for computers"

severe prawn
#

2

languid radish
#

In any programming language that just has log

#

ah thanks

willow bear
#

uh

#

no

#

first off it's likely not 2

#

and second you really have to ask your programming language's documentation

#

not us

severe prawn
#

:d

sturdy haven
#

Did I do these right

trim fable
#

question

#

how is

#

10^logx

#

=x ?

fluid shore
#

Well, suppose $log_{10} x = y$

obsidian monolithBOT
fluid shore
#

Then, you agree that:

$x = 10^y$

obsidian monolithBOT
fluid shore
#

?

#

@trim fable

trim fable
#

oh

#

ye

fluid shore
#

Now, think about what y is

#

Then, you'll have your answer

#

Okay?

trim fable
#

logx=log10^y

#

?

fluid shore
#

?

trim fable
#

do we solve or

#

something

fluid shore
#

No. $x = 10^y$, correct?

obsidian monolithBOT
trim fable
#

oh

fluid shore
#

What did we define y as, initially?

trim fable
#

but how did u get to that?

#

did u use

#

10^logx?

fluid shore
#

Nope

trim fable
#

oh

#

but i wanna know how

#

u get fromthat to just x

fluid shore
#

$a^x = y \iff x = \log_{a} y$

obsidian monolithBOT
fluid shore
#

That's how you get logarithms

trim fable
#

yeah im not good at logsss ahhhh

fluid shore
#

With some restrictions on what a is and y is, of course.

trim fable
#

they confuse melol

#

yeah

#

well i have another question

#

about domain and range

#

brb tho

#

one sec

fluid shore
#

Try them on your own first

trim fable
#

i did

#

i solved for them all

#

but now just have to do

#

domain and range and i did it for the first two but

#

do i use the graph method?

#

where u draw them out

#

and set the y and restrict

#

idk it was confusing i learned it today

fluid shore
#

Nope, you can do it analytically for all of them. You don't need to draw the graphs, though it will be good practise for you if you do draw them out.

trim fable
#

oh

#

so i cant just look at it and

#

state them?

#

oh also for example

#

like one of the examples was

#

f(x)=x+3 and g(x)=x^2-12

#

so then what we did was drew g(x) looked at the range and then

fluid shore
#

Why not just write things down?

trim fable
#

set that range as the domain of f(x)

#

so why do u do that^

fluid shore
#

??

trim fable
#

?

fluid shore
#

Do you know what composition of two functions is?

trim fable
#

yeah

#

f(g(x))

#

but then why are u using g(x) first

#

when its the inner one?

#

inner then outer function?

#

for these?

fluid shore
#

What do you mean 'why are u using g(x) first'?

trim fable
#

so like

#

drawing it first

#

then fx beside it

fluid shore
#

Why are you drawing them/

trim fable
#

and taking its range

fluid shore
#

?

trim fable
#

the graphs

#

coz my teacher

fluid shore
#

Why are you drawing them?

trim fable
#

told us

#

to draw

#

them

#

tho its

#

confusing

#

is there a different way to

#

state domain and range

#

without having to draw and then

#

use the range as the domain for f(x)

#

and then finding it

#

to see if its valid

fluid shore
#

Like I said, you can determine it analytically for the given functions. You don't have to draw the individual functions, though it's good practice.

#

You should actually just google these things. They're not that hard to learn online. Once you have learned them, apply them to your problems and then come back here if you're stuck.

trim fable
#

oh

#

ok

#

google what?

#

oh alright

#

tho what should i google?

fluid shore
#

Well, google the composition of functions and how to determine the range/domain of a composite function. They'll give you a whole bunch of results.

trim fable
#

ohhhhhh right

#

domain and range lol

fluid shore
#

Work through the examples you find, then work through your teacher's examples. Then, come back here if you're stuck with an actual step in your working

trim fable
#

of composites ok thats what i meant

#

ok

#

yeah i calculated f(g(x)) and g(f(x))

#

for all and checked the answrs and got them but

#

i dd the domain and range for the first 2

#

tho idk how to do c

#

coz u get

#

sqrt(4-x^4)

fluid shore
#

Okay then?