#help-42

1 messages · Page 73 of 1

candid pilot
#

@polar frost

polar frost
#

What do u mean?

polar frost
candid pilot
#

In the part I circled

#

Like is there supposed to be another line there or is it right

#

also how can i find the point of intercepts for f(x) = 6- x^2 and its inverse root 6-x

polar frost
#

No

#

For every x there should 1 value of f(x)

candid pilot
#

point of intersection i mean

#

would i use substitution and then solve?

polar frost
polar frost
#

Its a fact

#

Those x value has a corresponding f(x) and they're there

candid pilot
#

Oh that ones for a different question

polar frost
#

Im so confused

#

Whats the question again

candid pilot
#

Sorry well start a new question

#

how can i find the point of intersection for f(x) = 6- x^2 and its inverse root 6-x

polar frost
#

Like the intersection of the 2 lines?

candid pilot
#

yeah

polar frost
#

inverse root 6 - x like

candid pilot
#

oh sorry no like

#

f^1(x) = root 6-x

#

so originally i found the reciprocal of 6 - x^2

candid pilot
#

the next step was the point of intersection

polar frost
candid pilot
#

yeah

polar frost
#

Just set them =

candid pilot
#

i also substituted for y and got x^4 + 12x^2 + x +30 = 0

polar frost
#

6 - x^2 = sqrt(6-x)

candid pilot
#

yeah i wasn't able to factorise it

polar frost
#

square them

candid pilot
#

yeah and then i got x^4 - 12x^2 + x +30 = 0 is what i mean

#

and wasn't able to factorise it

polar frost
#

Use calculator then

candid pilot
#

is there any like way to do it without calculator?

polar frost
#

its a 4 degree poly

candid pilot
#

yeah so 4 intersections

polar frost
#

Only 2

candid pilot
#

oh 2?

#

but like for the root equation

polar frost
#

U need to restrict that sqrt

candid pilot
#

would you have a plus minus in front of it

polar frost
#

So x must be positive

#

discard the negative

candid pilot
#

okok

#

wait so

#

im a bit lost

#

i squared the square root meaning i squared both sides

#

and then i brought everything to the LHS

#

and got x^4 - 12x^2 + x +30 = 0

#

but im not sure how to solve for x so i can then substitute it and find y

#

unless this process is wrong

#

@polar frost

polar frost
#

then u should get 4 values of x

#

but u should only accept x > 0

candid pilot
#

Is it not possible without?

#

A calculator

calm coralBOT
#

@candid pilot Has your question been resolved?

calm coralBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

timber timber
#

Option 1: 2(lw + lh + wh), l + w + h, lwh Option 2: 3 layers of 10, 7 layers of 21, 3 layers of 21, 7 layers of 3. Option 3: volume, edge lengths, base area Option 4: equal to, less than, greater than
Image

timber timber
#

pls help 🙂

calm coralBOT
#

@timber timber Has your question been resolved?

timber timber
#

<@&286206848099549185>

#

i give up

#

.close

calm coralBOT
#
Channel closed

Closed by @timber timber

Use .reopen if this was a mistake.

calm coralBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

mortal heath
#

could i possibly get some help on this question? i'm just honestly quite confused on where to even start with this

polar frost
#

Set R(x) > 60

#

Then find x

brazen elbow
mortal heath
#

yeah i'm just confused on the > thing but should i just treat it as = when solving for x?

brazen elbow
polar frost
#

For that function y>60 only return x in positive

brazen elbow
#

without considering it, the answer is inconplete

mortal heath
#

wait so i should write it out as 60 > 7500x/x^2 + 2500?

polar frost
#

No?

#

its more than 60

mortal heath
#

ohhhhhhh

#

right sorry 😭

polar frost
mortal heath
#

i'm just confused because the final answer is a range

remote mural
#

there is some algebra you have to do

#

so like, do you understand that [
\4{7500x}{x^2+2500} \ge 60
]
is the inequality you are meant to solve

potent lotusBOT
mortal heath
#

yes

remote mural
#

ok

#

so a good way to start is to subtract 60 from both sides, and combine everything on the left to a single fraction

#

What does that get you

mortal heath
#

oh i thought it would be better to multiply each side by x^2 + 2500 to cancel out that fraction

glass heart
#

I would say its easier to multiply both sides by x^2+2500

remote mural
#

i mean sure the denominator goes away either way

mortal heath
#

yeah

glass heart
#

note that x^2+2500 is certainly >0, so you dont have to switch the inequality

mortal heath
#

so then i got that 60x^2 + 150000 < 7500x

#

yeah

#

or wait i can just send what i did

#

i know i should've put < instead of = but yea

#

i still don't think i got the right answer idk

polar frost
#

Bruh

mortal heath
#

maybe i'm stupid but i don't know what's wrong with that

polar frost
#

You should use the => arrow instead of -> this one

#

I thought u were substitute that part in

mortal heath
#

oh i didn't know that made a difference it's just kinda how i write stuff down for myself when working out

polar frost
#

😭

remote mural
#

it's not really important its fine, you can always just include the endpoints

polar frost
#

Hmm

remote mural
#

anyways

polar frost
#

Why the answer looks a bit wrong

remote mural
#

im pretty sure you erased a 0 from the 150000 @mortal heath

polar frost
#

Did u remove one 0 from 150000 to 15000

mortal heath
#

oh i did my bad 😭

remote mural
#

also just simplify all of ig

#

750, 15000, and 6 all divide 6

polar frost
#

Wait no

mortal heath
#

i got it thank you!!

polar frost
#

Did she devide everything by 10

mortal heath
#

i did yeha

remote mural
#

yeah i think its fine

#

anyways divide by 6 what do u get

polar frost
#

I use my calculator and get 25 100

#

So miku probably made a mistake when calculate x

mortal heath
#

yeah i did

#

my mistake was that i calculated with 1500 instead of 15000

#

i got the right answers fixing that haha

remote mural
#

yeah she erased a 0 like we said lmao

mortal heath
#

thank you! sorry if this work is really simple but i appreciate the help a lot 😭 need to pass this class

polar frost
#

2 values of x mean u need to limit it

mortal heath
#

yeah i set it as

#

25 < x < 100

polar frost
#

Good

mortal heath
#

thank you once again haha

#

.close

calm coralBOT
#
Channel closed

Closed by @mortal heath

Use .reopen if this was a mistake.

calm coralBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

lunar ridge
#

Please help

calm coralBOT
timid oracle
#

you can solve for x since the all the probabilities sum to 1

#

split that thing into P(B intersect A')/P(C)

calm coralBOT
#

@lunar ridge Has your question been resolved?

calm coralBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

fringe hamlet
calm coralBOT
fringe hamlet
#

Can the fraction be reversed when there is a + in the middle?

#

Like I did

fringe hamlet
#

On the penultimate line of the photo

ancient helm
fringe hamlet
#

Yes

ancient helm
#

like to go from the line above it to that?

fringe hamlet
#

Yes

ancient helm
#

well in general no

#

you should combine LHS into a single fraction

#

then cross multiply

#

LHS has common denom already

#

don't simplify the 3^(n+1)/3^(n+1) part

fringe hamlet
#

Ah ok

#

Thanks !

#

.close

calm coralBOT
#
Channel closed

Closed by @fringe hamlet

Use .reopen if this was a mistake.

calm coralBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

midnight field
#

working on triple integrals! what am i doing wrong here?

warm warren
midnight field
#

forgot that i wrote t

#

should be b

#

nothing else is changed i just had T in my notes and instinctually put it there

#

im confdent theres something wrong with the setup

warm warren
#

I don’t see it soz I’m very sleepy tho

midnight field
#

all good

#

im guessing its a dumb mistake somewhere i havent seen

#

Yup

#

forgot rho ^2

#

lmao

#

.close

calm coralBOT
#
Channel closed

Closed by @midnight field

Use .reopen if this was a mistake.

calm coralBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

uncut narwhal
#

Hi

calm coralBOT
#

Please don't occupy multiple help channels.

uncut narwhal
#

please help

#

934.38

#

i got that

unkempt drift
uncut narwhal
unkempt drift
#

I know but the steps are also important

#

It saves us from having to do your work again

thin gulch
calm coralBOT
#

@uncut narwhal Has your question been resolved?

calm coralBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

blazing coyote
calm coralBOT
blazing coyote
#

I split this into

#

$\int_{\frac{1}{3}}^{\frac{1}{2}}e^2dx+\int_{\frac{1}{2}}^1edx+\int_1^3dx$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

would that be right

#

if right that would be

#

$\int_{\frac{1}{3}}^{\frac{1}{2}}e^2dx+\int_{\frac{1}{2}}^1edx+\int_1^3dx=e^2\left(\frac{1}{6}\right)+\frac{e}{2}+2$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

just checked the answer key

#

it;s apparently 5/6

#

how is that?

rustic osprey
#

Did you remember the ln part

blazing coyote
#

what ln part

#

oh

#

so it would be the ln of these exponetial functions ?

rustic osprey
#

,w 2(1/2-1/3)+(1/2)

potent lotusBOT
blazing coyote
#

so $\int_{\frac{1}{3}}^{\frac{1}{2}}\ln\left(e^2\right)dx+\int_{\frac{1}{2}}^1\left(e\right)dx+\int_1^30dx=e^2\left(\frac{1}{6}\right)+\frac{e}{2}+2$

rustic osprey
potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

thanks!

rustic osprey
blazing coyote
#

.close

calm coralBOT
#
Channel closed

Closed by @blazing coyote

Use .reopen if this was a mistake.

blazing coyote
#

.reopen

calm coralBOT
#

blazing coyote
#

so I was thinkng of solving this by. breaking it down into seperate intervals

#

$\int_0^1xdx+\int_1^22x^2-1dx+\int_2^33x^3-2dx$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

would that be right

rustic osprey
blazing coyote
#

thanks!

clever ruin
#

another to try if u want

#

$\int_0^\infty e^{-\lfloor x \rfloor}dx$

potent lotusBOT
blazing coyote
#

hmm

#

let me think

#

thanks for the nice problem

#

hmm

#

so that would be

#

$e^0+e^{-1}+e^{-2}....$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

which is an infinite GP

#

which would be

clever ruin
#

yea

blazing coyote
#

$\frac{e}{e-1}..$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

clever ruin
#

yea

blazing coyote
#

thanks! That was fun

clever ruin
#

if u like integrals

#

there are Bees such as the MIT int bee and UK Integration Bee (Cambridge)

blazing coyote
#

I do solve them, that's where I get these problems from, Thanks though!

#

could you link to the cambridge bee

#

can't find it

bronze adder
blazing coyote
#

it is from the caltech one

clever ruin
blazing coyote
#

thanks!

#

I converted this into two forms

#

form a

bronze adder
#

utilize symmetry about pi/2 thonk

blazing coyote
#

$\left(\int_0^{\pi}\frac{\left(\sin\left(\frac{x}{2}\right)-\cos\left(\frac{x}{2}\right)\right)^2}{\left(\sin\left(\frac{x}{2}\right)+\cos\left(\frac{x}{2}\right)^2\right)}dx\right)$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

bronze adder
#

after some simplifcation it turns into tan^2(x/2) which is easy to integrate

#

oh lord

rustic osprey
#

If we’re doing integration then have another fun one
Hint: ||binomial theorem||

blazing coyote
#

thanks!

bronze adder
#

do you know how to get there

blazing coyote
#

thinking about it

bronze adder
#

alright

blazing coyote
potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

which is integrable

bronze adder
#

fair

rustic osprey
#

👋

blazing coyote
#

thanks a lot

bronze adder
#

for the 19th one ||you can split it as arctan(1 + x) - arctan(x)||

#

and the 20th is just ||an embellished euler log trig so thats -pi(ln 2)/2||

blazing coyote
#

spoilers !

bronze adder
#

mb

#

49 ||x --> 1/x and add||

rustic osprey
blazing coyote
potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
blazing coyote
#

$\int_0^{\frac{3\pi}{4}}1-\sec^2\left(x-\frac{\pi}{4}\right)+\int_{\frac{3\pi}{4}}^{\pi\ }1-\sec^2\left(x-\frac{\pi}{4}\right)=\frac{3\pi}{4}-\tan\left(\frac{\pi}{2}\right)+\frac{\pi}{4}-\tan\left(\frac{3\pi}{4}\right)-\tan\left(\frac{\pi}{\left(2\right)}\right)$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

what am I doing wrong here

#

oo

#

it should be x/2

#

$\int_0^{\pi}1-\sec^2\left(\frac{\pi}{4}-\frac{x}{2}\right)$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

whcih is $\pi-1$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

huh

#

the answer is 4-pi

#

,w integrate 1-sec^2(pi/4-x/2) from 0 to pi

blazing coyote
#

must have made a calculation mistake

#

nvm

#

thanks

blazing coyote
#

$\left(\int_0^{\infty}\tan^{-1}\left(\frac{\left(x+1-x\right)}{1+x\left(x+1\right)}\right)\right)$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

bronze adder
#

why do you surround the whole thing in parenthesis lol

blazing coyote
#

I'm using approach 0 for formatting

#

which is

bronze adder
#

dunno what that means but alright

blazing coyote
#

$\int_0^{\infty}\tan^{-1}\left(\left(x+1\right)-\tan^{-1}\left(x\right)\right)$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

bronze adder
#

whatever your approach 0 is

blazing coyote
#

which can be integrated by parts

bronze adder
#

its misplacing parenthesis willy nilly

blazing coyote
blazing coyote
bronze adder
blazing coyote
#

$\int_0^{\infty}\tan^{-1}\left(x+1\right)-\tan^{-1}\left(x\right)$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

,w $\int_0^{\infty}^{-1$\ln\left(x\right)\arcsin\left(x\right)-\int \frac{\arcsin\left(x\right)}{x}$$\int \frac{\ln\left(1-x\right)}{\sqrt{2x\left(1-x\right)}}$}\left(x+1\right)-\tan^{-1}\left(x\right)$

#

lol

#

thanks

bronze adder
#

use arctan

blazing coyote
#

yeah, will in the future, I think in this problem, getting it to this form was the hard part, so I'll skip evaluvating it for now

#

onto problem 20

#

$\int_0^1\frac{\ln\left(x\right)}{\sqrt{1-x^2}}$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

let $x=e^t$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

$\int_1^e\frac{te^t}{\sqrt{1-e^{2t}}}$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

bronze adder
#

-infinity to 0

blazing coyote
#

$\int_1^e\frac{te^t}{\sqrt{1-e^{2t}}}=t\sqrt{1-e^{2t}}=\int \sqrt{1-e^{2t}}$

#

ah

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

$\int_1^e\frac{te^t}{\sqrt{1-e^{2t}}}=t\sqrt{1-e^{2t}}-\int \sqrt{1-e^{2t}}$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

$\int_{\ -\infty}^0\frac{te^t}{\sqrt{1-e^{2t}}}=t\sqrt{1-e^{2t}}-\int \sqrt{1-e^{2t}}$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

let $e^t=u$ for the second part

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

I think I;ll just be going in circles if I do that

bronze adder
#

the IBP is

blazing coyote
#

let me IBP instead

bronze adder
#

not right thonk

bronze adder
#

shouldn't it be arcsin(e^t)

blazing coyote
#

oh yeah

#

it should

#

that makes in much harder IMO

bronze adder
blazing coyote
#

$t\arcsin\left(e^t\right)-\int \arcsin\left(e^t\right)$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

bronze adder
blazing coyote
#

I think I better IBP the first function instead

bronze adder
#

easy enough though just multiply and divide by e^t i'd think

blazing coyote
bronze adder
#

sure try it out

blazing coyote
#

$\ln\left(x\right)\arcsin\left(x\right)-\int \frac{\arcsin\left(x\right)}{x}$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

which isn't integrable afaik

#

hmm

bronze adder
#

,w integrate arcsin(x)/x

blazing coyote
#

oo

blazing coyote
#

king's rule

#

maybe

bronze adder
#

F

blazing coyote
#

which would be

#

$\int \frac{\ln\left(1-x\right)}{\sqrt{2x\left(1-x\right)}}$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

nah

#

that won't work either

#

hmm, maybe I use a polynomial approximation for bith functions

#

and integrate that

bronze adder
#

you cant approximate this stuff

blazing coyote
#

hmm

bronze adder
#

the choices are all closed form

blazing coyote
#

let me think some more

#

,w integrate te^t/\sqrt{1-t^2}

blazing coyote
#

oo

#

$\int \frac{\ln\left(x\right)}{x\sqrt{\frac{1}{x^2}-1}}$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

let $ln(x)=u$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

so that gives

#

nvm

bronze adder
#

same thing as before

#

do you want a hint

blazing coyote
#

yes please

bronze adder
#

trig sub

blazing coyote
#

hmm, x=sin(t)

#

so dx=cos(t)dt

#

$\int \frac{\ln\left(\sin\left(t\right)\right)}{\cos\left(t\right)}\cos\left(t\right)dt$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

which is integrable

#

oof

#

that was easy

#

thanks!

bronze adder
#

its not

#

,w integrate ln(sin x)

blazing coyote
#

oh

bronze adder
#

you need to use more properties and stuff to get it

#

the definite case is doable

blazing coyote
#

hmm

#

ok

#

hmm

#

$\int_0^{\frac{\pi}{2}}\ln\left(\sin\left(t\right)\right)+\ln\left(\cos\left(t\right)dt\right)$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

this is 2I

#

is it -pi/2 ln(2)

#

$\int_0^{\frac{\pi}{2}}\ln\left(\sin\left(t\right)\cos\left(t\right)\right)dt\ $

#

$\int_0^{\frac{\pi}{2}}\ln\left(\frac{\sin\left(2t\right)}{2}\right)dt\ $

#

$\int_0^{\frac{\pi}{2}}\ln\left(\frac{\sin\left(2t\right)}{2}\right)dt$

bronze adder
#

no space after the last character

bronze adder
potent lotusBOT
#

ƒ(Why am. I here)=I don't know
Compile Error! Click the errors reaction for more information.
(You may edit your message to recompile.)

blazing coyote
#

thanks

#

now to try this

blazing coyote
cursive linden
bronze adder
#

1 + x + x^2 in the denominator always screams a sub

blazing coyote
#

yeah

#

$x=tan(u)$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

bronze adder
#

not what I meant but keep going 🫠

blazing coyote
#

hmm

#

let me think of something else

cursive linden
#

first keep going with what you were thinking sippy

blazing coyote
#

$\int_0^{\frac{\pi}{2}}\frac{\sec^2\left(u\right)}{\sec^2\left(u\right)+\tan\left(u\right)}$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know
Compile Error! Click the errors reaction for more information.
(You may edit your message to recompile.)

blazing coyote
#

$\int_0^{\frac{\pi}{2}}\frac{u\sec^2\left(u\right)}{\sec^2\left(u\right)+\tan\left(u\right)}$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know
Compile Error! Click the errors reaction for more information.
(You may edit your message to recompile.)

blazing coyote
#

nah

#

I'll try some other sub

#

$\int_0^{\infty}\frac{\arctan\left(x\right)}{\tan\left(\operatorname{arccot}\left(x+1\right)-\operatorname{arccot}\left(x\right)\right)}$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know
Compile Error! Click the errors reaction for more information.
(You may edit your message to recompile.)

blazing coyote
#

nah, that won't work either

#

maybe I IBP

#

that definietly won't work

#

I guessing I have to do something to the denom

#

write it in terms of trig functions , is that right?

cursive linden
#

keep trying ig 🤷‍♂️

blazing coyote
#

hmm

bronze adder
#

what have I returned to

blazing coyote
#

$\int_0^{\infty}\arctan\left(x\right)\tan\left(\arctan\left(x+1\right)-\arctan\left(x\right)\right)dx$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

bronze adder
#

do you wanna know what id do

blazing coyote
#

No

#

please

bronze adder
#

alright

#

keep going

blazing coyote
pure breach
#

r u even doing that thonk

blazing coyote
#

did that long ago

pure breach
blazing coyote
#

$\int \frac{\arctan\left(x\right)}{\left(1+x\right)^2-x}$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

blazing coyote
#

I feel like an inverse trig sub may help here

pure breach
#

not really imo but u can try

blazing coyote
#

hmm

#

ok

#

in that case I think I have to express the denom as an inverse trig function?

pure breach
#

that seems to be it

blazing coyote
#

so this is what I thought of

#

which I don't think helps very much

pure breach
#

arctan a - arctan b might? unsure

blazing coyote
#

ah

#

that's where I went wrong

pure breach
#

wdym?

blazing coyote
#

$\int \arctan\left(x\right)\left(\arctan\left(x+1\right)-\arctan\left(x\right)\right)$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

pure breach
#

oh 💀

blazing coyote
#

am i right until here

pure breach
#

i have no idea what u subbed

blazing coyote
#

no sub yet

pure breach
#

wth r u doing then 💀

blazing coyote
#

just tried re-writing 1/(1+x+x^2)

#

that's why I wrote it as $tan\left(\arctan\left(x+1\right)-\arctan\left(x\right)\right)dx$

potent lotusBOT
#

ƒ(Why am. I here)=I don't know

pure breach
#

but thats wrong no?

#

oh wait mb

#

am dumb

pure breach
blazing coyote
#

but that isn't integrable , is it?

#

this

pure breach
#

i dont think u can solve this normally

#

u might need something more higher-end

blazing coyote
#

hmm

#

maybe eularian trig

pure breach
#

i am trying feynman 🙂

blazing coyote
#

That's way beyond me

pure breach
#

tbh it isnt

#

as long as uk partial diff

#

which everyone knows as long as they r good at differentiation

#

hmm feynman gives something that i might be able to partial frac

blazing coyote
#

oof

#

that works

pure breach
blazing coyote
#

why am I so slow, lol

pure breach
blazing coyote
#

I forgot about it

#

thanks

#

.close

calm coralBOT
#
Channel closed

Closed by @blazing coyote

Use .reopen if this was a mistake.

pure breach
#

well if u want i can show u the feynman way @blazing coyote

#

its pretty easy that way

calm coralBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

remote mural
calm coralBOT
remote mural
#

How do I prove this obvious statement

atomic idol
#

construct a bijection between the sets

remote mural
atomic idol
#

the subsets don't have all the same elements

remote mural
#

One has n the other does not

atomic idol
#

A and B are different sets, they just have the same cardinality

remote mural
#

Ok

remote mural
atomic idol
#

for any $A \in \mathcal{A}$ it corresponds to the set $A \cup {n} \in \mathcal{B}$

remote mural
#

What

#

I don’t understand

potent lotusBOT
#

Awesam

atomic idol
#

what did you learn as the method

atomic idol
#

so you're not looking for a formal proof just intuition?

remote mural
#

But how do I do a formal proof

#

Using BP

atomic idol
#

what's BP

remote mural
#

I wasn’t taught how to use bijective principle

#

(BP)

atomic idol
#

oh

#

yeah then you do it the way I described

remote mural
#

What even is it

atomic idol
#

do you know what a bijection is

remote mural
#

No

#

It’s like one to one

atomic idol
#

yes

remote mural
#

When u map it

#

Each element corresponds to 1 other element

brisk pelican
#

And onto

remote mural
#

Ex: {1,2,3,4,5} and {5,6,7,8,9}

atomic idol
#

yes so if you map a set $A$ to a set $A \cup {n}$ then this is a 1 to 1 correspondance between $\mathcal{A}$ and $\mathcal{B}$

potent lotusBOT
#

Awesam

atomic idol
#

for example if I have the set ${1, 2, 3}$ then it maps to the set ${1, 2, 3, n}$

potent lotusBOT
#

Awesam

atomic idol
#

then every set maps to a different set and every set containing n is accounted for

remote mural
#

1,1 2,2 3,3 it’s one to one and onto

#

Because n has no element mapped

#

Surjective

#

I’ll show u my proof

remote mural
atomic idol
#

okay

remote mural
ancient helm
#

that's not onto

#

also that's not even what A and B look like

#

A is the set of all subsets not containing n

#

B is the set of all subsets containing n

calm coralBOT
#

@remote mural Has your question been resolved?

remote mural
remote mural
#

But I don’t understand that

ancient helm
#

He gave you the correspondence

remote mural
#

?

#

Which correspondence

ancient helm
remote mural
ancient helm
#

You map the subset not containing n

#

To the exact same subset but with n

remote mural
#

Ok

#

Half contain n half don’t

#

?

remote mural
#

Yes but depends what n is

ancient helm
#

No

remote mural
#

There is one to one correspondence

#

?

ancient helm
#

Yes you're trying to show this mapping is a bijection

#

So you need to show it's injective and surjective

remote mural
ancient helm
#

Yes

#

Surjective = onto

#

Injective = one to one

remote mural
#

What does onto mean

#

One to one means the mapping goes 1 element for each corresponding

#

But onto?

#

Sorry I never learnt this lol

ancient helm
#

Let f:A -> B then f is onto if for every b in B, there exists an a in A with f(a)=b

remote mural
#

I see

#

And one to one means that f(a2) neq to f(a1)

ancient helm
#

if a1 and a2 are distinct

remote mural
#

Yes

#

So it’s obviously one to one the set

ancient helm
#

How is it obvious

remote mural
#

Because each subset will be different

ancient helm
#

Yes but why wont f map different subsets to the same thing

remote mural
#

The sets which hold the subsets are equal caridinality I mean

remote mural
#

Cuz I’m still lost I can’t visualize anything

#

@ancient helm can u show me an example?

#

Let’s say i take the set X={1,2,3}

ancient helm
#

Ok

#

What is A and what is B

remote mural
#

A = {{1,2},{1},{2},{}}

#

Since n = 3

ancient helm
#

yes

#

What is B

remote mural
#

B = {2,3},{3}, {1,3},{1,2,3}

#

Oh nvm

#

A and B are equal in cardinality

ancient helm
#

That's not what B is

remote mural
#

Is it that?

ancient helm
#

Youre missing {1,2,3}

#

And in A you're missing the empty set

remote mural
#

Oh

ancient helm
#

Ok now show me the mapping

remote mural
ancient helm
#

Yes

#

Now prove it for general sets X

remote mural
#

Ok

ancient helm
#

You need to show your map is injective and surjective in your proof

remote mural
ancient helm
#

That's why you need to generalize

#

Not explicitly write out the mapping

remote mural
remote mural
#

?

#

Half contain n, half don’t

#

So I’ve proved it but not by BP 😂

remote mural
#

Ok first how do I prove that it’s is invective (ie at least 1 x connects to exactly 1 y)

#

<@&286206848099549185> can someone tell me how to prove injectivity?

amber roost
potent lotusBOT
#

3ndlyb Alabyd

remote mural
amber roost
calm coralBOT
#

@remote mural Has your question been resolved?

untold compass
#

idk what BP is but you can pair up items in A and B to prove it

#

like {stuff without n} pairs with {same stuff with n added}

#

and that hits everything

calm coralBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

calm coralBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

proper panther
#

im having a tough time understnading logical statements and negations. could someone verify that my process is correct for these problems?

calm coralBOT
#

@proper panther Has your question been resolved?

proper panther
#

.close

calm coralBOT
#
Channel closed

Closed by @proper panther

Use .reopen if this was a mistake.

calm coralBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

keen grove
#

how do I solve this?

calm coralBOT
keen grove
#

this is what ive done so far

lethal oak
#

you know how log laws work right

keen grove
#

yeah

lethal oak
#

do you think u can apply it here

keen grove
#

so do i do ln((1+4R^2)/1+R^2))? i dont see how that helps tho

lethal oak
#

oh brother it helps

#

what can you do with limits here

#

in this situation

#

given that you have a inside function nested inside an outside function

keen grove
#

idk

#

what can u do?

lethal oak
#

Can you not push the limit inside if the limit inside exists?

keen grove
#

inside the log?

lethal oak
#

yes

keen grove
#

ahhh ok

lethal oak
#

you see now

keen grove
#

ohh then its 1/2(ln(4))

#

right i see

lethal oak
#

mhmmm

keen grove
#

thanks for that

lethal oak
#

np

keen grove
#

.close

calm coralBOT
#
Channel closed

Closed by @keen grove

Use .reopen if this was a mistake.

calm coralBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

mossy wigeon
calm coralBOT
mossy wigeon
#

Where did the random 2 come from

#

Also why the bounds of integration was changed

neon sage
#

,w plot 1-x^2

neon sage
#

notice how the function is symmetric about x = 0

#

so instead of integrating from -1 to 1, we integrate from 0 to 1 and double the value

mossy wigeon
#

its the same thing

#

like

#

i dont need to change it

#

but

#

its for

#

easiness

calm coralBOT
#

@mossy wigeon Has your question been resolved?

neon sage
mossy wigeon
#

ty

#

.close

calm coralBOT
#
Channel closed

Closed by @mossy wigeon

Use .reopen if this was a mistake.

calm coralBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

novel jackal
#

yo

calm coralBOT
novel jackal
#

I don't understand why f(x) is a bijection from the natural numbers to the positive rational numbers

#

in there example, there is never any rational number greater than 1 in there list

#

Because of that, isn't this a bijection from the natural numbers to all rational numbers between 0 and 1?

#

So why did they claim its a bijection from the naturals to all positive rationals?

clear delta
#

you're right

novel jackal
#

wait so is the slide wrong

#

HA

swift laurel
#

an actual example for your reference, from wikipedia (note that the red numbers are duplicates and are discarded)

calm coralBOT
#

@novel jackal Has your question been resolved?

#
Channel closed

Closed by @novel jackal

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

remote mural
#

I have to prove

$Z_1 \bar{Z_2} + Z_2 \bar{Z_1} = 2 |Z_1| |Z_2| \cos (\theta_1 - \theta_2)$

clear moat
#

great!

remote mural
clear moat
#

now, is Z and Z^C complex numbers

remote mural
#

Z1 and Z2 are complex numbers, the $\bar{}$ represents their conjugates and $\theta_1 \ and \ \theta_2$ represent their arguments respectively

potent lotusBOT
#

fredthebread69

clear moat
#

fair enough what did you try

remote mural
#

I have tried putting $Z1 = |Z1|e^{i\theta}$

potent lotusBOT
#

fredthebread69

#

fredthebread69

clear moat
#

try using the respective form for complex numbers

#

$$z_1 = r_1 (\cos \theta_1+ i \sin \theta_1)$$

potent lotusBOT
#

ℕaive

clear moat
#

$$z_2 = r_2 (\cos \theta_2+ i \sin \theta_2)$$

potent lotusBOT
#

ℕaive

remote mural
#

Can I not use exponents and try?

clear moat
#

sure if you feel so

remote mural
#

Could you help me out?

calm coralBOT
#

@remote mural Has your question been resolved?

remote mural
#

<@&286206848099549185>

#

I think I'm doing something wrong

calm coralBOT
#

@remote mural Has your question been resolved?

green haven
#

(idk if it's helpful actually i just noticed it immediatly)

remote mural
#

It would help if someone knew what the name of the identity haha

#

And yes it's an identity

green haven
#

yea is it possible to visualise the LHS as what was usual in that identity?

#

ir transpose/convert etc

#

somehow idk

remote mural
green haven
#

like if u think about it the cos rule works out the square of the side opposite the angle

#

now u have angle and the 2 sides

#

can u make z1__z__2+__z__1z2 into that somehow

remote mural
#

The cosine rule?

green haven
#

yea

calm coralBOT
#

@remote mural Has your question been resolved?

remote mural
#

.close

calm coralBOT
#
Channel closed

Closed by @slate atlas

Use .reopen if this was a mistake.

calm coralBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

austere moth
#

Let $f(x, y, z) = 14 + x^3y^4e^{x(z+4)}$ and $A = (1, 1, −4)$ \
(a) Specify the tangent plane to the level surface f(x, y, z) = 15 at point A.\
(b) At what rate of change $f′_v (A)$ does f increase or decrease in the direction (−6, 2, −3) away from the point A? \
(c) In what limits does the directional derivative $f_v (A)$ depending on the departure direction v away from A?

austere moth
potent lotusBOT
#

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

austere moth
#

Anyhow.... i have a formula for calculating the tangent plane

#

Does this formula work with f(x,y,z)

#

or is specifically f(x,y,)

potent lotusBOT
#

themadchessplayer

#

themadchessplayer

clever loom
#

Where v is the direction

austere moth
#

Hold on, do I just input the point A into the formula essentiallly to get the tangentplanes equation?

clever loom
#

Yes

austere moth
#

one sec ! c:

#

You mean this right?

clever loom
#

I don't understand what you want in (c)

clever loom
austere moth
#

Oh

clever loom
#

Because the surface is f(x,y,z)-15 = 0

austere moth
#

oh i see

#

how do i handle the -15?

#

I assume i dont?

clever loom
#

Vanishes when you take derivative

austere moth
#

Ah right makes sense

#

god ur good at this haha

#

don't you dare leave

clever loom
#

LOL

#

Please clarify c

#

If you want an answer for that

austere moth
#

"In what limits varies the directional derivative $f'_v (A)$ depending on the direction of departure v from A"

potent lotusBOT
#

Merineth

austere moth
#

It's written in very poor swedish so a little hard to translate it sadcat

clever loom
#

Are you asking for minimum and maximum values of f_v'(A)?

austere moth
#

I honestly have no idea, it's written in very poor swedish to begin with so it's quite unclear

#

I could ask my teacher for more clarification

clever loom
#

Please do so. There is no point attempting a question which is unclear

austere moth
#

either way, do i need to handle the triangle differently?

#

Cant remember what it's called

#

delta?

#

gradient?

potent lotusBOT
#

themadchessplayer

clever loom
#

Otherwise part (c) does not make sense

clever loom
austere moth
#

Oh ok! And gradient is a derivative vector?

clever loom
#

Transpose of derivative (Jacobian) matrix

austere moth
#

"The gradient of a line is the measure of the steepness of a straight line." seems right?

#

But i can't just inpout a,b,c into the fornula right?

#

I have to do something with the gradient?

clever loom
austere moth
#

$\nabla F(1,1,-4) \cdot (x-1, y-1, z+4) = 0$

potent lotusBOT
#

Merineth

clever loom
potent lotusBOT
#

themadchessplayer

austere moth
#

the gradient of that point will give a value, right?

clever loom
#

Gradient is a vector

austere moth
#

Oh, i thought gradient was to calculate the slopes incline / decline

#

Is this the one i should use ?

clever loom
#

Yes

#

You might have confused with divergence, but that has nothing to do with slope

austere moth
#

Hmm yeah i might have to do some repetition on it

#

Either way

#

$\nabla f(x) =$

potent lotusBOT
#

Merineth

austere moth
#

x is in bold, does that mean it's a vector?

#

I don't have a vector, i have a point

#

Are you sure i can use that formula to calculate the gradient?

rare anchor
#

hi can any body help with a question for solving a differential equation?

calm coralBOT
rare anchor
#

oh

austere moth
#

@upper sparrow sadcatthumbsup

clever loom
austere moth
#

So i want to use this part?

clever loom
#

Yes

austere moth
#

Why is f lowercase here but uppercase on the formula for calculating the tangentplane?

clever loom
#

That's the third or fourth time you asked this

clever loom
#

For functions

austere moth
#

$\nablda f(1,1,-4) = (\frac{\partial f}{\partial x} (1,1,-4), ... )^T$

potent lotusBOT
#

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

calm coralBOT
#

@austere moth Has your question been resolved?

austere moth
#

Got a little trouble with the derivatives

#

$\frac{\partial f}{\partial x} = 14+x^3y^4e^{x(z+4)}$

potent lotusBOT
#

Merineth

austere moth
#

14 is a constant so it disappears

#

I think i have to use product rule here to derive x^3 and e^(x(z+4))

#

However i'm not sure what happens with y^4 when i try to apply product rule

#

$x^3y^4e^{x(z+4)}$

potent lotusBOT
#

Merineth

austere moth
#

Specifically this part

#

$y^4(x^3 * e^{x(z+4)})$

potent lotusBOT
#

Merineth

austere moth
#

I guess i can apply the product role within the helpparens

#

$\frac{\partial f}{\partial x} = 14+x^3y^4e^{x(z+4)}$

potent lotusBOT
#

Merineth

austere moth
#

<@&286206848099549185> Can someone please help me with deriving this expression with respect to x

#

I understand that the constant 14 dissapears

#

and that i can apply the product rule to

#

$y^4(x^3e^{x(z+4)})$

#

But i just can't seem to get the right answer...

potent lotusBOT
#

Merineth

timid oracle
#

partial derivative of this wrt to x?

austere moth
#

Yea

timid oracle
#

yeah just use product rule

#

treat z+4 as a constant

austere moth
#

$y^4(3x^2e^{x(z+4)} + x^3(z+4)e^{x(z+4)})$

potent lotusBOT
#

Merineth

timid oracle
#

Yeah i think

austere moth
#

,wolf derive with respect to x (14+x^3y^4e^(x(z+4)))

timid oracle
#

thats same

austere moth
#

I tried simplifying but i'm not getting the same afaik?

timid oracle
#

pretty sure it is

austere moth
#

glad to hear

#

and when i do with respect to y then it's literally the same?

#

except 4y^3

#

,w derive with respect to y (14+x^3y^4e^{x(z+4))

austere moth
#

,w derive with respect to z (14+x^3y^4e^{x(z+4))

austere moth
#

uh why does x^3 become x^4?

#

nvm

austere moth
#

Does it seem right?

#

I never utilized 15 tho?

#

So i might have done it wrong?

austere moth
#

<@&286206848099549185> :(

calm coralBOT
#

@austere moth Has your question been resolved?

austere moth
#

.close

#

.close

calm coralBOT
#
Channel closed

Closed by @austere moth

Use .reopen if this was a mistake.

calm coralBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

silent sinew
#

hello, i am trying to prove {0,1} is an albien group under ⨁.

modern peak
#

you mean

#

abelian?

ancient helm
#

do you mean $\mathbb{Z}_2$?

potent lotusBOT
#

chebyshev's infinite pee norm

silent sinew
#

yesh

ancient helm
#

because that's defintely not closed

silent sinew
modern peak
#

fyi {0, 1} isn't really a group

silent sinew
#

uh oh

modern peak
#

you need to define the operation ;-;

#

it could be addition, multiplication, anything...

silent sinew
modern peak
#

we can't really figure out what u mean

silent sinew
#

this is what the connective means

modern peak
modern peak
ancient helm
#

it's not the same

silent sinew
#

its logic

ancient helm
#

unless

#

1 = true

#

and 0 = false

silent sinew
#

yes its logic

ancient helm
#

ok

silent sinew
#

groups in logic

ancient helm
#

it's just xor

silent sinew
#

so for set A ={1,0} is {A, ⨁} a abelian group

silent sinew
ancient helm
#

it is

silent sinew
#

ok

#

so for abelian group

ancient helm
#

what have you done so far

silent sinew
#

give me a sec breh

#

we need it to be closed

#

which it is because its always either gonna be 1 or 0

#

associative

#

which idk how to prove but maybe if i do truth tables for theta ⨁ phi and then phi ⨁ theta and they equal thats enough proofg

#

identity i really dont know how to do

#

inverse i really really dont how to do

ancient helm
#

i think i would just write out the multiplication table if i were you

silent sinew
#

multiplicatiom table?

#

or truth table

ancient helm
#

yeah truth table

silent sinew
#

yeh done that

ancient helm
#

show

calm coralBOT
#

@silent sinew Has your question been resolved?

silent sinew
#

srry am back

#

one sec for phi ⨁ theta trusth table

#

phi ⨁ theta is same truth table

#

so it is commutative

#

composition table is wrong

#

is diagonal

#

but anyway

#

what is the identity element

#

@ancient helm come back 😢

ancient helm
#

,rotate

potent lotusBOT
silent sinew
ancient helm
#

please fix the tables on the right but yes

ancient helm
#

there's only two options, true or false

silent sinew
#

yeh

#

identity means that for any element in the group

#

if it undergoes the operation then it stays the same

#

oh it’s 0

#

just by looking at the truth tables

ancient helm
#

if it undergoes the operation then it stays the same

#

if it undergoes the operation with the identity then it stays the same

silent sinew
#

yeh srry

#

row 2 and 4 it goes unchanged

#

so 0 is the identity

ancient helm
#

yes identity is 0

silent sinew
#

okay nice

#

now inverse

#

for inverse when it goes through the operation it goes to the identity

#

and we know the identity is 0

#

first and last row

#

and it is the same

#

so it’s inverse is itself?