#help-28

1 messages · Page 235 of 1

slate shuttle
#

bro canu draw (if u want)

raw quartz
#

I think it’s orthogonal to the plane

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Not an orthogonal plane

analog shale
#

suppose that OB=r, find O

slate shuttle
# analog shale

Hmmmm🤔 but it seems like its imposible we to find exact o we have to find a range

#

but ima try this

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Hold on

analog shale
#

we are just assuming the radius is r for now

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we will try and find what r is later

slate shuttle
#

Like this?

analog shale
analog shale
slate shuttle
slate shuttle
#

Fine imatry

analog shale
hidden fractal
#

ok i think i got the answer to this so i can maybe help try to explain now??

analog shale
hidden fractal
#

okk so in order to minimise the radius we assume (11,9) is a point on the circumference

analog shale
hidden fractal
#

um if its not on the circumference the circle can be smaller i would have thought

#

i could be tripping though, it is late at night right now

analog shale
hidden fractal
#

ok fine i dont need that step for right now

#

anways i would call the center C

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and try to work out the line that both b and c are on

slate shuttle
#

İf you get this i ll explain others

torn jolt
slate shuttle
analog shale
slate shuttle
analog shale
#

you didn't prove that

analog shale
torn jolt
slate shuttle
#

Lies inner region of a circle

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*lines

#

Am inwrong?

analog shale
#

where A is not on the circumference of the circle

torn jolt
analog shale
slate shuttle
#

Yes, you are right, but wouldn't it make our job easier to accept it like this because it asks us for its smallest value?

analog shale
#

you can see that there is a leap in your argument, by claiming that A lies on the circumference of the circle

torn jolt
#

not on the circle

analog shale
#

but yeah you got the same point as mine

#

OP is assuming it lies on the circle

hidden fractal
#

inside would mean approaching the boundary i presume

#

so we can count touching the boundary

analog shale
slate shuttle
#

What would you do if I asked you what is the smallest value of x+3, where x is an integer greater than 5?

#

Think this

analog shale
#

because a minimum value does not exists

torn jolt
#

don't you think we are making it more complicated?there must be an easy way to do

analog shale
hidden fractal
#

i am sure that A lies on the circumference, but i doubt it even matters

#

have u worked out the line that O must be on

#

@slate shuttle

analog shale
slate shuttle
#

You write x+3>8, that is, you take it as if it is equal to 8, then if it is greater than 8, you say the smallest 9, right?

analog shale
slate shuttle
torn jolt
#

I think we should retranslate the que to verify if it's right or not

hidden fractal
hidden fractal
#

yea its painful

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you can see something so clearly

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but u just can't prove it

slate shuttle
#

Yes i cant probe it

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İm thinking how to explain it hmm

hidden fractal
#

it seems v useful

analog shale
slate shuttle
#

Okay guys letme look at it again.

slate shuttle
analog shale
#

@hidden fractal is your answer on the options they gave?

slate shuttle
analog shale
slate shuttle
#

I got something

analog shale
#

are they asking for radius or diameter?

hidden fractal
#

please tell me we know the equation of the purple line now

#

it is extremely useful

analog shale
#

but no radius less then 6 is on the option list

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they must be asking for diameter

hidden fractal
#

what diagram

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is the radius 5.9

analog shale
slate shuttle
hidden fractal
#

the squares represent length 2 tho

analog shale
#

oh wait

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i messed up one bit

slate shuttle
analog shale
#

nvm

slate shuttle
#

İ found this..

hidden fractal
#

i get r>sqrt(50) as well

slate shuttle
hidden fractal
#

i think my method was less clean than this tho

analog shale
slate shuttle
hidden fractal
#

no

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i used it to draw diagrams

analog shale
hidden fractal
#

i literally cant draw a circle for my life

slate shuttle
hidden fractal
#

i did a really stupid method

analog shale
slate shuttle
analog shale
#

when you got r=5\sqrt 2?

slate shuttle
#

Bro its the only possible choice you can try if u want

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i didnt find any other

analog shale
hidden fractal
#

considering its not an olympiad level problem where ur getting rigoursly marked i think making this assumpition is safe enough

slate shuttle
#

Bro you realy right

analog shale
analog shale
slate shuttle
#

but like i said only 5root2 fit there

torn jolt
analog shale
torn jolt
#

y=x

raw quartz
#

$B\left(7,7\right)$ and Tangent line $T = 14-k$ such that center $C\left(k,14-k\right)$ then radius $r = \mathcal{D}\left(C, B\right)$ such that $\mathcal{D}\left(A,C\right)<r$ then, $r = \mathcal{D}\left(C, B\right)= \sqrt{2}\left|k-7\right|$ and $\mathcal{D}\left(A,C\right) = \sqrt{\left|11-k\right|^2 + \left|k-5\right|^2}$ such that $2\left(k^2 -14k + 49\right)>\left(121-22k+k^2\right)+ \left(k^2-10k+25\right)$

slate shuttle
analog shale
#

this is the solution i had in mind too

hidden fractal
#

hm does anyone want to do a fun number theory problem then

slate shuttle
#

but it's intuition using a little bit of logic, after all, the 3-4-5 triangle should come to mind there.

slate shuttle
analog shale
hidden fractal
analog shale
#

@slate shuttle try and see if you follow Shoshir's solution

analog shale
torn jolt
slate shuttle
torn jolt
#

Nah I got that you simplify it

analog shale
slate shuttle
#

İ dont think im able do this

analog shale
#

just lmk

slate shuttle
#

Why r=D(C,B)

glossy valveBOT
#

Shoshir

raw quartz
#

made a mistake with greater than srry

slate shuttle
torn jolt
#

r=|k-(14-k|/√1²+1² = |2h-14|/√2 = √2|h-7|

analog shale
torn jolt
#

don't take OA on circle

slate shuttle
#

yeah makes sense🤔

analog shale
#

so since the circle is tangent to y=x, CB is the radius

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so r=D(C,B) (here we set radius to r)

torn jolt
#

now compare the prev eq and value of r as √2(h-7)

slate shuttle
#

Go on

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Pls contunie

torn jolt
#

you'll get h=12

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put the value of h in r=√2(h-7)

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youll get the integer

slate shuttle
#

makes sense🤔

analog shale
torn jolt
#

he wrote differently

slate shuttle
#

this problem was hard xd

raw quartz
#

Simplified, $2k^2 - 28k + 98 > 2k^2-32k+146$ then $-28k>-32k+48$ and $4k>48$ so therefore $k>12$ and $r=\sqrt{2}\left|k-7\right|$, so $\min\left\lbrace \mathcal{D}\left(C,B\right)\right\rbrace = \lim_{k\to 12} \sqrt{2}\left|k-7\right| + \epsilon $ therefore $\min\left\lbrace \mathcal{D}\left(C,B\right)\right\rbrace = 5 \sqrt{2} + \epsilon$

glossy valveBOT
#

Shoshir

analog shale
#

you didnt define it

slate shuttle
torn jolt
#

the coordinates of center

slate shuttle
analog shale
slate shuttle
#

need limit in this circle

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İm not that smart

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I think I'll go with intuitive😵‍💫

torn jolt
analog shale
raw quartz
glossy valveBOT
#

Shoshir

torn jolt
#

distance formula

raw quartz
analog shale
#

closed and bounded below gives inf in the set

analog shale
#

im just saying u compact is too strong for this

raw quartz
slate shuttle
raw quartz
analog shale
glossy valveBOT
#

Shoshir

analog shale
#

heine borel

raw quartz
#

I forgot about the bounded part

slate shuttle
#

guys 1 more bullet?

torn jolt
raw quartz
torn jolt
#

it is the point to line distance formula

slate shuttle
raw quartz
slate shuttle
#

sure?

raw quartz
analog shale
glossy valveBOT
#

qwertytrewq

analog shale
#

where did you get $(2h-7)/\sqrt 2$?

glossy valveBOT
#

qwertytrewq

torn jolt
slate shuttle
#

A polynomial P(x) of degree 4 with real coefficients satisfies the inequality P(x)>=x for every real number x.
P(4)=?

analog shale
#

u essentially just did (14-h,h)

torn jolt
#

yup (h,14-h)

slate shuttle
raw quartz
glossy valveBOT
#

Shoshir

slate shuttle
analog shale
slate shuttle
raw quartz
#

$P\left(1\right)=1 \\ P\left(2\right) = 4 \\ P\left(3\right)=3$

glossy valveBOT
#

Shoshir

slate shuttle
analog shale
slate shuttle
#

i aggre

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But sadly there something i cant explained to u

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maybe its because i trNSLATED it wrong idk

analog shale
raw quartz
#

$a+b+c+d+e = 1 \\ 16a+8b + 4c +2d + e = 4 \\ 81a+27b+9c + 3d + e = 3$

glossy valveBOT
#

Shoshir

slate shuttle
#

İ still looking a simple way to explain it to you

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but there is still something i didnt realy understand about the question too because the turkish is problematic too

analog shale
slate shuttle
#

İdk what is rolles therom. Sory

slate shuttle
analog shale
slate shuttle
#

😄😃

raw quartz
glossy valveBOT
#

Shoshir

torn jolt
slate shuttle
crude kayak
raw quartz
#

$\exists x \in \left[2,3\right], \quad \partial P\left(x\right)<0$

slate shuttle
glossy valveBOT
#

Shoshir

slate shuttle
torn jolt
#

Q(x)=P(x)-x

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Q(1)=P(1)-1=1-1=0

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check for 1,2 and 3

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youll find the next step then

raw quartz
#

$\int_{\left[2,3\right]} P\left(x\right),dx ,= -1$

glossy valveBOT
#

Shoshir

torn jolt
#

?,what are you doing

raw quartz
analog shale
slate shuttle
#

@raw quartz
Hint:

analog shale
raw quartz
#

$P^{-1}\left(3\right) = P\left(3\right) \ P^{-1}\left(4\right) = \frac{P\left(2\right)}{2} \ P^{-1}\left(1\right) = P\left(1\right)$

glossy valveBOT
#

Shoshir

slate shuttle
#

@raw quartz

analog shale
crude kayak
raw quartz
#

$A\left(x\right) = P\left(x\right)-x \ A\left(x\right) = \left(x-3\right)\left(x-1\right)\left(x-r\right)\left(x-s\right)$

glossy valveBOT
#

Shoshir

slate shuttle
crude kayak
slate shuttle
#

Mb

crude kayak
slate shuttle
#

Hoursmof slepness..

analog shale
slate shuttle
#

1minutw

analog shale
#

degree 4

analog shale
crude kayak
analog shale
crude kayak
#

google translate is a great invention

raw quartz
#

$A\left(2\right) = 2r + 2s - rs - 4 \ P\left(2\right) = 2r+2s - rs - 2 \ 2r+2s-rs-2 = 16a+8b+4c+2d+e$

glossy valveBOT
#

Shoshir

slate shuttle
#

Thats ıt..

analog shale
#

or rolle

slate shuttle
analog shale
crude kayak
#

the choices aren't fractions

raw quartz
#

$A\left(4\right) = 3rs - 12r - 12s + 48 \ P\left(4\right) = 3rs - 12r - 12s + 52$

glossy valveBOT
#

Shoshir

analog shale
slate shuttle
#

whats wrong?

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İt should be true

analog shale
slate shuttle
#

💀

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Fr?

analog shale
#

yeah you drew a 7 under the 22 opencry

slate shuttle
#

🤨🤨🤨🤨

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Bro

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its eniugh today ig

raw quartz
#

$A\left(4\right) = 3\left(s-4\right)\left(r-4\right)$

glossy valveBOT
#

Shoshir

slate shuttle
raw quartz
#

$P\left(4\right) = 3\left(s-4\right)\left(r-4\right) + 4 \geq 0$

glossy valveBOT
#

Shoshir

slate shuttle
#

😑

#

Did you even look at what i send?

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Guys we are here lik 3 hours

raw quartz
#

$P\left(x\right) = ax^4 + bx^3 + cx^2 + x\left(d+1\right) $

analog shale
#

,texsp ||Set $A(x):= P(x)-x$, then $A(x)\geq 0$. Since $A(1)=0$, we clain that $A'(1)=0$, suppose $A'(1)\neq 0$, then local injectivity tells us that there exists a neighborhoud $(1-\epsilon,1+\epsilon)$ such that $A$ is injective. But this implies that either $A$ will be negative somewhere, which is a contradiction. Therefore $A'(1)=A(1)=0$ (one can also directly compute the limit to see that $A'(1)=0$). This means that $1$ is a double root of $A$. SImilarly $A'(3)=A(3)=0$ so $3$ is a double root of $A$. Since $A$ is degree $4$ it follows that $A(x)=c(x-1)^2(x-3)^2$. Plugging in $A(2)=2$ yields $c=2$ and thus $P(4)=22$.||

slate shuttle
analog shale
glossy valveBOT
#

qwertytrewq

raw quartz
#

$\frac{P\left(4\right)}{3s-12} + \frac{8}{3}= r$

glossy valveBOT
#

Shoshir

raw quartz
#

$P\left(4\right) = P\left(4\right) + 8s - 28$

glossy valveBOT
#

Shoshir

raw quartz
#

$s=\frac{7}{2}$

glossy valveBOT
#

Shoshir

analog shale
analog shale
raw quartz
glossy valveBOT
#

Shoshir

analog shale
#

so it should be c(x-3)(x-1)(x-r)(x-s)

analog shale
glossy valveBOT
#

qwertytrewq

analog shale
#

why is $c=1$?

glossy valveBOT
#

qwertytrewq

analog shale
#

it is not given that $P,A$ is monic

glossy valveBOT
#

qwertytrewq

raw quartz
#

$\frac{-3P\left(4\right)}{2}+3 = 0$

glossy valveBOT
#

Shoshir

raw quartz
#

$P\left(4\right) = 2 C$

glossy valveBOT
#

Shoshir

analog shale
glossy valveBOT
#

qwertytrewq

analog shale
#

want to find $3 c r s - 12 c r - 12 c s + 48 c$, given $-c r s + 2 c r + 2 c s - 4 c=2$

glossy valveBOT
#

qwertytrewq

analog shale
#

I am pretty sure lagrange interpolation say that there are infinitely many set of solutions

full forumBOT
#

@slate shuttle Has your question been resolved?

full forumBOT
#
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full forumBOT
#
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thick hedge
#

Trying to find the extrema using Lagrange multipliers

onyx glen
#

so you have $\mathcal L(x,y,\lambda) = x^2 + y^2 - \lambda(xy - 1)$, yes?

glossy valveBOT
thick hedge
#

wait

#

how did you get that

onyx glen
#

or plus λ(xy-1)... i don't actually remember what the convention it but it also might not matter

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yeah sorry plus

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other than that tho it is a lagrangian like any other

thick hedge
#

I was thinking $\grad{x^2+y^2} = \lambda\grad{xy}$

glossy valveBOT
#

What a wonderful world !

austere cove
#

You solve xy = 1 for 0, because LMs only work with constraints set to 0, iirc

onyx glen
thick hedge
#

This is what I was taught

onyx glen
#

that remark doesnt apply in your form

#

but i mean ok this is basically just the same thing restated in a different format

#

also

#

suggest writing gradients and shit as columns sometimes

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$\div(x^2 + y^2) = \bmqty{2x \ 2y}$

glossy valveBOT
onyx glen
#

\\ for newline inside a matrix

umbral dome
thick hedge
#

so $\bmqty{2x \ 2y}= \lambda \bmqty{y \ x}$

glossy valveBOT
#

What a wonderful world !

thick hedge
#

Which is sort of sus

#

Wait no

#

$2x = \lambda y ; 2y = \lambda x; xy=1$

glossy valveBOT
#

What a wonderful world !

thick hedge
#

I have to solve this system of equations

onyx glen
#

yes

thick hedge
#

so $4(xy) = \lambda(xy)$.
\
So $\lambda =4$
\
We thus have
$2x= 4y$
\
$2y=4x$
\
Whose only solution is $(0,0)$.
\
However, $0 \cdot 0 \neq 1$

glossy valveBOT
#

What a wonderful world !

onyx glen
#

hold up

#

intuition says we did miss something

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oh yes you did

#

it's $4xy = \lambda^2 xy$

glossy valveBOT
thick hedge
#

ah

onyx glen
#

whence $\lambda = \pm 2$ not 4.

glossy valveBOT
thick hedge
#

yea

#

but I think this doesn't change anything

onyx glen
#

it changes a lot actually

#

you actually get solutions this time

thick hedge
#

wait, I get 2x=2y, so x=y

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so the entire line x=y as a solution

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That gives me $2x^2$

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no?

glossy valveBOT
#

What a wonderful world !

thick hedge
#

wait, no

onyx glen
#

what is the intersection if any between the line x = y and the curve xy = 1

thick hedge
#

the constraint gives me x^2=1

onyx glen
#

that's it?

#

it consists of just one point?

thick hedge
#

that and (-1,-1)

onyx glen
#

it consists of just those two points?

thick hedge
#

yes

onyx glen
#

are you sure?

thick hedge
#

yea

onyx glen
#

ok yes you're correct

thick hedge
#

Thanks!

onyx glen
#

now look at the other case

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i.e. λ = -2

thick hedge
#

hmm

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well, that's x=-y

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which has no solutions

full forumBOT
#

@thick hedge Has your question been resolved?

#
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austere cove
#

@thick hedge

thick hedge
#

.reopen

full forumBOT
#

austere cove
#

This problem should have a solution

thick hedge
austere cove
#

Specifically at (1, 1) just from a geometric analysis

#

Oh.

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I'm late to the party

onyx glen
#

we found (±1, ±1) yes

austere cove
#

Oooh, I just read the bottom

#

My bad

#

.close

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eternal dock
#

hey, I have two functions F and f. f=1/(x^2+1), and F'=f, I'm technically not supposed to be able to find F(x) and I'm supposed to prove F(x)+F(-x)=0 for each x in R

gilded matrix
#

@eternal dock

#

is R for real number?

eternal dock
#

yes

onyx glen
#

is F(0) fixed as 0 though

eternal dock
#

yes

onyx glen
#

right

eternal dock
#

sorry forgot to mention

gilded matrix
#

?

onyx glen
#

anyway $F(x) \overset?= -F(-x)$ seems reasonably easy to prove by integral manipulation

glossy valveBOT
gilded matrix
#

I can do it but I m not getting the question

eternal dock
#

oh

#

my mind didn't go there

gilded matrix
#

it's given that F'=f but we have to find for F

eternal dock
#

is there no way to prove that F is an odd function

gilded matrix
#

?

eternal dock
onyx glen
onyx glen
rugged void
#

derivative of an even func is always an odd func

#

🫠

onyx glen
#

but how do you know that the antiderivative of an even function is always odd

rugged void
#

is it not, smh?

eternal dock
rugged void
#

oh frick i misread it

#

that is absolutely mb

eternal dock
#

well if the derivative of an even function is odd

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that means that for f which is the derivative of F, and even, F has to be odd?

gilded matrix
#

I think we have to use integration at some point

onyx glen
#

are we allowed to refer to integrals in any way, shape or form at all or no @eternal dock

eternal dock
#

yes

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just not solve integral of 1/x^2+1dx

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we haven't learnt tan sub

eternal dock
onyx glen
rugged void
#

that's... fairly elementary to see?

#

also like you can literally just... show that if F' is even, F is odd

#

just... write the statement down for F' being even and integrate

eternal dock
rugged void
#

try it

#

what'd the statement for "F' is even" be

eternal dock
#

f(-x)=-f(x)

rugged void
#

mmm no

#

that's an odd function

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and we know that f is even

eternal dock
#

yea not the -

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my brain isn't working

#

prove that d/dx F(x)=d/dx F(-x)

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from that we get f(x)=f(-x)

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therefore F is odd

#

?

eternal dock
rugged void
#

now try to integrate both sides--left side is easy, but the RHS will require a very basic application of the chain rule

eternal dock
#

we're not supposed to be able to integrate that yet since we haven't learnt tan substitution

rugged void
#

...

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not in explicit form dude

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but we know that F'(x) = f(x)

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and therefore, F'(x) = F'(-x)

#

you can integrate that

eternal dock
#

F(x)=-F(x)

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which is what we want to prove

rugged void
#

that's literally it, yes

#

two/three lines

#

smh

#

😭

eternal dock
#

fair enough

#

thank you

#

.close

full forumBOT
#
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Remember:
Ask your math question in a clear, concise manner.
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After 15 minutes, feel free to ping <@&286206848099549185>.
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thorny shuttle
#

how do i proceed i tried replacing x-> -x

onyx glen
#

why not put x = -1

rugged void
#

i was so confused when i saw this because i was like is this not just that

thorny shuttle
#

i am pretty sure i gotta take limits

onyx glen
#

what

#

what do you mean "not really"

#

are you saying that putting x=-1 is illegal somehow or what

thorny shuttle
#

try putting x =1

#

hol up wait i can do -1

rugged void
#

not

#

x = 1

#

yeah-

thorny shuttle
#

for 1 i gotta put limit

#

right

#

got it

rugged void
#

😭

thorny shuttle
#

cuz 0/0 indeterminate

#

nvm

rugged void
#

...

thorny shuttle
#

complex numver moment

onyx glen
#

-1 is not the same thing as 1

#

not even in R

thorny shuttle
#

i mean yeah

#

i didnt consider that

#

lmao

sudden cargo
#

are you supposed to make a generating function?

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#

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cursive trout
#

help me pls

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cursive trout
#

im new in matrices

#

A is 2*2 matrix = [2 1 -3 4]

#

B is 2*1 matrix [7 6]

#

A*X = B

#

find X

#

help ples

pure basin
#

Uh

cursive trout
#

yeaah

#

?

pure basin
#

ok so

#

ax=b

cursive trout
#

yes

#

yes

pure basin
#

x=a^-1b

cursive trout
#

hmm

pure basin
#

Find a inverse

cursive trout
#

idkk

#

man i am in standard 10th

#

indi

pure basin
#

Then why are you doing this

cursive trout
#

india

#

icse

pure basin
#

Learn the basics?

cursive trout
#

this is in our syllabus

cursive trout
#

addition

#

subtraction

#

multiplication

pure basin
#

You don't know inverse of a?

cursive trout
#

but dont know division

#

nope

pure basin
#

There is no division

cursive trout
#

waht is inverse

#

aahh whatever

pure basin
#

For a 2x2 matrix

#

[ 1 2
3 4]

#

Do you know determinant?

cursive trout
#

no

pure basin
#

(1 * 4) -(2 * 3) gives us the determinant

cursive trout
pure basin
#

I assume you have no 3x3 matrix

cursive trout
#

and then

cursive trout
#

only 2x2 and 2x1 in syllabus

pure basin
#

a^-1 = adjoint(a)/determinant(a)

cursive trout
#

adjoint?

pure basin
#

Yes

#

For a 2x2 matrix there is a trick

#

To easily find it

cursive trout
#

okay waht is that

pure basin
#

But you need to know what is adjoint

cursive trout
#

what is it?

pure basin
#

Or I think you will learn next year

cursive trout
#

hmm

#

so what to do now

pure basin
#

So the trick is basically

#

[4 -2
-3 1]

#

You swap the diagonal and add negative to the other 2

#

So adjoint is the transpose of a cofactor matrix

cursive trout
#

okaay, i am pretty much unable to understand whatever u are saying

pure basin
#

Ok

rose zephyr
#

$$
{\begin{bmatrix}
a & b \
c & d \
\end{bmatrix}}^{-1}

\frac{1}{a d - b c}
\begin{bmatrix}
d & -b \
-c & a \
\end{bmatrix}
$$

pure basin
#

Woah

#

so its bmatrix for a matrix ok

rose zephyr
#

I missed the determiant

#

One se

pure basin
#

Oh yea

#

What u said is adjoint

#

@cursive trout you don't know cofactors?

glossy valveBOT
#

StrangeQuarkAL

cursive trout
pure basin
#

Then how can you even solve that question

#

Wait I think we need to

#

Yeah I think it's that way we need to guess it

#

So do you know what is order of a matrix

#

No need to find inverse

cursive trout
#

no easy method with simple arithmetics

pure basin
#

There is

cursive trout
pure basin
#

Ok

#

so you gave a 2x2 matrix

cursive trout
#

hmm

pure basin
#

and we need to find x which is a x b matric

#

now the answer is a 2x1 matrix right?

cursive trout
#

yes

pure basin
#

Which means we need t multiply with a 2x1 matrix?

cursive trout
#

so X much be 2x 1

#

yes

pure basin
#

So just put [a b]

#

And solve ur linear equation

#

in 2 variables

cursive trout
#

i cant understand what u saying

pure basin
#

Write down

cursive trout
#

ax = b

pure basin
#

yes

cursive trout
#

x = b/a

pure basin
#

multiply a matrix no

#

Division is NOT POSSIBLE

#

MATRIX division NO

cursive trout
#

what to mutiply witj

pure basin
#

So the best way to find AX=B

#

Would be X=A^-1B

#

But you don't know what is A^-1

#

So we multiply AX

cursive trout
#

yes

#

ax

pure basin
#

Multiply AX

cursive trout
#

how we multiplay ax

pure basin
#

What is ur A

cursive trout
#

[2 1
-3 4]

pure basin
#

Yes

#

Now your X=[a b]

rose zephyr
#

Do you not know matrix multiplication @cursive trout ?

pure basin
#

wait did i see it right

cursive trout
#

ewin?

pure basin
#

[7 6] is a 2x1 ok

cursive trout
pure basin
#

ok then multiply [ 2 1 -3 4] with [a b] = [7 6]

cursive trout
rose zephyr
#

$$
\begin{bmatrix}
2 & 1 \
-3 & 4 \
\end{bmatrix}
\begin{bmatrix}
a \
b \
\end{bmatrix}
$$

pure basin
glossy valveBOT
#

StrangeQuarkAL

pure basin
#

U just said u know matrix multiplication

cursive trout
pure basin
#

Then do it

cursive trout
#

but how did

pure basin
#

?

cursive trout
#

X = [a
b]

rose zephyr
pure basin
#

because we don't know x

#

but we know it has to be a 2x1 matrix

cursive trout
#

okayy

#

okay okay

#

understood

#

thankssssssssssss

pure basin
#

For 3x3 matric the a^-1b would be best but 2x2 you can just solve a linear equation

cursive trout
#

thnkkk u so muchh

#

thnksssss

pure basin
#

if done .close

cursive trout
#

.close

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#
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elder saddle
#

The probability of at least 3 . Would be the inverse of what . In the problem there’s 6 experiments I was thinking using binomcdf 3 but I’m not sure

gritty flax
#

?

elder saddle
#

What would be the way to solve for the probability of at least 3

#

I can show the problem big that helps

gritty flax
#

P(X >= 3) ?

#

Its the same as 1 - P(X<3)

elder saddle
#

So what would I enter binomcdf 2?

#

That doesn’t sound right

#

I know to use the compliment rule

gritty flax
#

Thats complement rule

#

And yeah P(X < 3) = P(X <= 2)

elder saddle
#

Can you elaborate I mean cause P(X<3) could also be 1 or P (X<=1 ) too right

gritty flax
#

I don't get what you said but no P(X < 3) = P(X<= 2) cuz in terms of integers

#

n < 3 => n <= 2

elder saddle
#

Why do you use 2 wouldn’t 1 suffice as well

gritty flax
#

?

elder saddle
#

Bro

gritty flax
#

Why would 1 be sufficient?

elder saddle
#

I’m asking

gritty flax
#

Yeah but why do you think so ?

elder saddle
#

Because it’s less than 3 if you’re saying the P(X<3)

gritty flax
#

Yeah cuz at least include the 3

#

So complement of P(X>= 3)

#

Is P(X < 3)

#

And since the number are integers

#

X < 3 => X <= 2

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#

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#
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formal quiver
#

There are four circles and four straight lines how many number of highest intersect point possible?

celest tapir
#

what are the types of intersections you expect?

full forumBOT
#

@formal quiver Has your question been resolved?

formal quiver
#

8×4=32

#

@celest tapir

celest tapir
#

there are more

formal quiver
#

Could you tell me how?

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#

@formal quiver Has your question been resolved?

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main scroll
#

How do we ! Decimal numbers

full forumBOT
main scroll
#

Ex:
$3 3.14!$

glossy valveBOT
#

Kakapo | Kakapo

soft quiver
#

why the factorial?

main scroll
#

I meant how do we factorial decimals

soft quiver
#

i don't get it

umbral dome
#

there is an extension to the factorial called the gamma function which can accept decimal inputs

soft quiver
#

true but does the op mean the same?

umbral dome
#

the gamma function can be computed with an integral

#

,, \Gamma(x) = (x-1)! = \int_0^\infty t^{x-1} e^{-t} \odif t

glossy valveBOT
main scroll
#

Do we do like
$1.11.21.31.41.5$ for factorials

glossy valveBOT
#

Kakapo | Kakapo

soft quiver
#

no

soft quiver
main scroll
#

.close

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#
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scenic brook
#

quick question

full forumBOT
scenic brook
#

can we not differentiate this as we would to b^f(x) ?

onyx glen
#

no because the base x is not constant

scenic brook
#

oh ok

#

so how would we go about differentiating this

amber robin
#

Do you know about logarithmic differentiation?

scenic brook
#

yes

#

log both sides?

amber robin
#

Yes

celest tapir
glossy valveBOT
scenic brook
#

oh that too

#

right right

#

okok thanks

celest tapir
#

logarithmic differentiation works too

#

you'll get the same thing after subbing in y

amber robin
glossy valveBOT
celest tapir
#

lol

amber robin
#

x^n formula + a^x formula

celest tapir
#

multivariable chain rule

amber robin
#

It works yk

celest tapir
#

yes

twin wolf
#

so extra catthimc

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#

@scenic brook Has your question been resolved?

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graceful pollen
#

im still so confused, i understand it but still get the wrong answer
need help with c and D

amber robin
graceful pollen
#

honeslty i do not knoq

#

know

amber robin
#

What did u get for A and B?

graceful pollen
#

a and b i got right

#

this is the answer

#

c and d wrong

amber robin
#

Wtf is this?

graceful pollen
#

idk ask my school why they teaching us this

#

this is the chapter subject

#

i think i know how to do it

#

by looking at the answers

#

let me see

#

yeah nvm.

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#

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slate shuttle
#

Now that we have equality.
What is the value of the definite integral?

celest tapir
#

Apply it once

#

What do you get?

slate violet
#

tan(0 + pi/2 - x) is...

slate shuttle
#

İ stuck here

celest tapir
#

what has bro written

#

Call the integral I

slate shuttle
glossy valveBOT
celest tapir
celest tapir
#

replace x with 0 + π/2 - x

slate shuttle
celest tapir
#

so what does tan (0 + π/2 - x) become?

slate shuttle
#

Help

celest tapir
#

do you not know what tan (π/2 - x) is

slate shuttle
#

But

#

İts not helping

celest tapir
#

it will help

#

what is it?

slate shuttle
#

🤯

#

😵‍💫

celest tapir
#

come on man, trust the process

#

if you're being uncooperative it's gonna affect you

slate shuttle
#

Like this?

celest tapir
#

Yes!

#

okay

#

okay good

#

now add those two representations of A

slate shuttle
#

Hmmmmmmm🤔🤔🤔🤔🤔🤔

#

Pi/4 ?

celest tapir
#

yes

slate shuttle
#

Bro what would you rate this?

celest tapir
#

rate what?

slate shuttle
#

Problem

celest tapir
#

it's fairly standard, you'll encounter this method of adding the integral to itself after manipulation many times

#

idk man like 7/10 for concept

celest tapir
#

with?

slate shuttle
#

Another

celest tapir
#

depends on the problem

slate shuttle
#

f'(2)=?

#

İdk where to start

celest tapir
#

hmm

#

okay yeah

#

so first partially differentiate wrt x

glossy valveBOT
celest tapir
#

now if you substitute x and y to be 1 you'll have f'(2) = f'(1) + 2

#

oh wait nvm

slate shuttle
#

Hmmmmmmm🤔🤔🤔🤔🤔🤔🤔🤔

celest tapir
#

tbf if you sub x = 0 you have

#

f'(y) = f'(0) + 2y

#

and you can solve for f now

#

f(y) = f'(0)y + y^2 + C

slate shuttle
#

İ didnt gwt it

celest tapir
slate shuttle
slate shuttle
celest tapir
#

now replace all x with 0

glossy valveBOT
celest tapir
#

okay?

slate shuttle
#

You mean f'(x+y)=f'(x)?

celest tapir
#

huh?

slate shuttle
celest tapir
celest tapir
#

which you can integrate both sides of wrt y

glossy valveBOT
celest tapir
#

all good?

slate shuttle
#

😵‍💫

slate shuttle
celest tapir
#

we're finding f(x)

slate shuttle
#

Hmmmmmm🤔🤔🤔 okey

#

Aaaaaa i find f(2)=3t then

celest tapir
#

Oh wait bro we're given f'(0) = 3

#

you didn't tell me that

#

😭

slate shuttle
#

Yes

celest tapir
#

well anyways

slate shuttle
#

İ find f'(2)=3

celest tapir
#

now we know that $f(x) = C + 3x + x^2$

glossy valveBOT
slate shuttle
#

Hmmmmmmmm🤔🤔🤔

celest tapir
slate shuttle
#

Oh okey😓

celest tapir
slate shuttle
#

Hmmmmmm🤔🤔🤔🤔

celest tapir
#

so we know that $f(x) = x^2 + 3x - 1$

glossy valveBOT
celest tapir
#

now all you gotta do is differentiate it once and plug in 2

slate shuttle
#

2x+3=7

celest tapir
#

yes

slate shuttle
#

Thx

#

But

#

İ would skip this if i saw something like that

celest tapir
#

lol that's up to you

slate shuttle
celest tapir
#

8/10

slate shuttle
celest tapir
#

open a new channel

#

frankly i'm quite tired i don't know if I can

slate shuttle
#

.close

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#
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stuck loom
#

Find the roots of x^{9}-x^{8}-8x^{7}+8x^{6}+22x^{5}-22x^{4}-23x^{3}+23x^{2}+6x-6.

stuck loom
#

$x^{9}-x^{8}-8x^{7}+8x^{6}+22x^{5}-22x^{4}-23x^{3}+23x^{2}+6x-6$

glossy valveBOT
#

Mathematician

onyx glen
celest tapir
#

,w Find the roots of x^{9}-x^{8}-8x^{7}+8x^{6}+22x^{5}-22x^{4}-23x^{3}+23x^{2}+6x-6.

cerulean cargo
#

lol wtaf

celest tapir
#

oof

onyx glen
#

well, i suppose this is quite the speedy solution to that.

#

but OP won't like this.

celest tapir
#

i wanted to check if it was doable

onyx glen
#

it is.

cerulean cargo
celest tapir
#

symmetric nonomial

onyx glen
#

x=1 is guessable (or you can spot the obvious term grouping) and once you factor it out you're left with a quartic in x^2

cerulean cargo
#

oh ok i see

winter rune
drowsy ivy
#

,w 1+1

analog shale
#

i suspect

onyx glen
onyx glen
winter rune
analog shale
winter rune
#

not like that

#

and ik there is a general solution for quartics, but i dont think that is expected

analog shale
fervent owl
winter rune
analog shale
winter rune
#

its
||x^4 - 8x^3 + 22x^2 - 23x + 6||

fervent owl
#

judging by the Wolframalpha output, ||x^2=2 and x^2=3|| are guessable roots

analog shale
winter rune
fervent owl
#

so then you can factor out ||x^2-2 and x^2-3||

analog shale
#

and there is.

fervent owl
#

||what you have left you can solve with repeated application of quadratic formula||

winter rune
analog shale
full forumBOT
#

@stuck loom Has your question been resolved?

#
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slender rose
#

How do i exactly calculate sin and cos of numbers?

hot herald
#

depends

sand escarp
#

of numbers?

grave elm
onyx glen
#

and which numbers

full forumBOT
# slender rose How do i exactly calculate sin and cos of numbers?

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

slender rose
#

I want to know how sine waves even work in the first place

slender rose
slate violet
slate violet
onyx glen
# slender rose I want to know how sine waves even work in the first place

Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now: https://www.khanacademy.org/math/algebra2/x2ec2f6f830c9fb89:trig/x2ec2f6f830c9fb89:unit-circle/v/unit-circle-definition-of-trig-functions-1

Extending SOH CAH TOA so that we can define trig functions for a broader class of angles

Practice this less...

▶ Play video
wild sleet
#

you know how they work

#

find x, draw a vertical line, you get y

#

nobody calculates them on their own, it's a calculator thing

#

you can do this though

sand escarp
#

Yes, this is pretty much how cos or sine of any number is calculated, together with trig identities I assume

slate violet
wild sleet
#

only to come up with it, there's no calculus in using it

slate violet
#

ah true