#help-17
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is this correct
and if it is how can i simplify that further
the f'(x) in red says 2e^(2x) js might have erased it
pro what kinda derivative is this shit?
u could not pay me to solve this shit
aw hell nah
LMAO
yeah i'd use some form of online calculator
okay ill do that now
my denominators were different to wolfram
if its (g(x))^2 its just ((x^2 + 1)^3 * (1 + sin(x)^5)^2
so why is it 4 and 6
noooo integrating it wouldve been so much worse omd
yeah was about to say, no fucking way am I integrating that
also i think u typed it in wrong?
u typed in e^2 * x rather than e^2x
Is that calculus?
yes
i mean i cant be asked to do this myself but i assume there must be some cancellation of sort somewhere
oh you mean theyd cancel out like some (x^2 + 1) and (1 + sin(x)) term in the numerator and denominator
is there a website where i can check if my answers correct just in a different form
i think wolfram alpha can simplify expressions?
,w differentiate (e^(2x))/( ((x^2)+1)^3 (1+sinx)^5)
i have a headache cuz im sick af so i cbf, but gl
,w simplify ((2e^(2x))(x^2 + 1)^3 * (1 + sin(x))^5 - (e^(2x))(6x(x^2 + 1)(1 + sin(x))^5 + (x^2 + 1)^3 * 5cos(x)(1 + sin(x)))/((x^2+1)^6 * (1 + sin(x))^10)
Wolfram Alpha doesn't understand your query!
Perhaps try rephrasing your question?
Click here to refine your query online
okay ping when
Will probably take me bout 10 mins so bear with me
@royal kestrel Has your question been resolved?
Begin with the equation we want to differentiate
[ y=\frac{e^{2x}}{(x^2 + 1)^3 (1+\sin x)^5} ]
Take the natural log of both sides and simplify using logarithm rules
[ \ln y = \ln (\frac{e^{2x}}{(x^2 + 1)^3 (1+\sin x)^5}) ]
[ = \ln e^{2x} - \ln ((x^2+1)^3(1+\sin x)^5) ]
[ = 2x - 3\ln (x^2 + 1) - 5\ln (1+\sin x) ]
Differentiate both sides with respect to $x$, note that $y$ is a function of $x$ and must therefore be differentiated implicitly (chain rule)
[ \frac d{dx} \ln y = \frac d{dx}( 2x - 3\ln (x^2 + 1) - 5\ln (1+\sin x) ) ]
[ \frac 1y \frac{dy}{dx} = 2 - \frac{6x}{x^2+1} - \frac{5\cos x}{1+\sin x} ]
So we have
[ \frac{dy}{dx} = y\cdot \frac{2(x^2+1)(1+\sin x) - 6x(1+\sin x) - 5\cos x(x^2+1)}{(x^2+1)(1+\sin x)} ]
Now simplify the numerator
[ \frac{dy}{dx} = y\cdot \frac { (1+\sin x)(2(x^2+1)-6x)- 5\cos x(x^2+1)}{(x^2+1)(1+\sin x)} ]
[ = y\cdot \frac { 2(1+\sin x)(x^2-3x+1)- 5\cos x(x^2+1)}{(x^2+1)(1+\sin x)} ]
Sub in the original $y$
[ \frac{dy}{dx} = \frac{e^{2x}}{(x^2 + 1)^3 (1+\sin x)^5}\cdot \frac { 2(1+\sin x)(x^2-3x+1)- 5\cos x(x^2+1)}{(x^2+1)(1+\sin x)} ]
[ = \frac{ e^{2x}(2(1+\sin x)(x^2-3x+1)- 5\cos x(x^2+1)) }{ (x^2+1)^3(1+\sin x)^5 \cdot (x^2+1)(1+\sin x) } ]
Simplify as needed
[ \therefore \frac{dy}{dx} = \frac{ 2e^{2x}(1+\sin x)(x^2-3x+1) - 5e^{2x}\cos x(x^2+1) }{ (x^2+1)^4(1+\sin x)^6 } ]
@royal kestrel
hope this helps
yeah mb, also missed some other 2s, let me fix it all
shsgd
I think that's everything
yeah
logs are very powerful
maybe look up some videos on logarithmic differentiation if you want a more in depth explanation
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For which one
for (f/g)(x)
Yes
the x^2 over x-1
Isn't $x^2+1=(x+1)(x-1)$
w
ohhh I see
That's wrong
ohhh
oh how
$x^2-1=(x-1)(x+1)$
w
yes it should be
yooo this made me giggle
x^2+1/x-1
then I am not sure if that's the answer or if I cross out the x and one
anyone else doesnt like this notation
I am not sure what you mean
divide them directly using long division or synthetic division
? how else would u write it
$\frac{f(x)}{g(x)}$
Obotron
(f/g) is it's own function
u define it like this
i understand that: in that case you would denote: $h(x) = \frac{f(x)}{g(x)}$
Obotron
nah more letters is unnecessary
yeh its fine. just lazy notation
like say u want (f/g)'
h'(x)
it doesnt matter but its not popular notation for a reason
okay thank god I would hate to try to synthetically divide
nevermind i trolled
misha
that's arguably less simple
this is what happened when I entered into mathaway
I think you can technically do synthetic division but as problem it want x^2 over x-1
I have a feeling f is supposed to be x^2 - 1
the answer in the first picture should be it
what are you saying?
although I guess since you are looking at composition of functions you can probably just leave it as x^2 + 1 / x-1
ignore that, I meant it was possible f was a typo
yeah I think so
ohh alright
but it doesn't ask to simplify so probably not
@daring marsh Has your question been resolved?
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hello
Send the question
understand?
yes
Which part?
im still confused
trigon in geometry or trigon in calc?
It would be nice if there's a specific problem that u stuck on
Cause "input the formula" is a bit vague
Dont u have homework or assignment?
yea but its schoolwork so teacher took it back
Search the internet or ur book
@charred violet Has your question been resolved?
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my bad i need to go
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okay
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help pls
use diffrence of squares formula
so 6?
yeah
Closed by @tight sedge
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np my guy
✅
?
use rise/run
wdym?
id just check the ratio of each triangle side to the corresponding side of T
T has a height of 2 and a length of 3
if they are equal then its similar
so c would be similar
How do you conclude that?
it has a scale factor of 2
yes
D
Again, how do you conclude that?
wait can something be similar if its rotated?
so it cant be d or a or c
Why not A?
its a and f
ok
is 2/3
ye
2/3 is the same as 20/30
yes
ye
now these other triangles might have the same ratio.
You check that by looking at how much they rise, and how much they run.
Try seeing the rise and run on triangle A
4:6
Nice!
Woohoo.
no probs!
Closed by @tight sedge
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.reopen
✅
I mean, you can factorise the equation or simply multiply into the parantheses.
i tried but it doesnt seem to work
Or something smarter.
Show me what you tried.
Ok
keep in mind the question wants two answers
Just factor
A is one of them
Chill man, I know the guy.
?
Micos...
My bad
if you give it away they can't find the solution organically
which arguably defeats the point of learning
Doorbell.
Nobody told op to click on the spoiler
We're not here to discuss amongst how to help.
fr
Just let it go.
What did I even do
Nothing man.
Alright bibalek.
yes
Can you show me what you intuitively think is the way to get the answer?
To help me see your thought process.
well factorisation
Oh, so you know that!
ye
now i have
it logged me out so i got new questions
oh.
Ah ok.
so we can still work it out
Sure.
Do you want a trick?
go for it
ye
the catmullah
u good
The c-value in your original equation
that's exactly it.
The other guy is wasting your time @tight sedge
Mean.
nah
But true
he helped with other questions
It took me 10 seconds to find that image
lots of them
lol
No matter what, you don't disrespect other people like that.
What was disrespectful
What I stated was a factual description of events
That’s not what he quoted lmao
nearly the same thing
Reposting for reference
Now please leave.
u good
Basically, this is telling you, that the two values shown here:
Will, multiplied together, give the c-value of a 2nd degree polynomial.
So, from all the answers there.
From A to H
The possible ones are more easy to find with this rule.
And to narrow it down even more.
ohhhh
The product of those values put together, also give the b-value
*sum
man
My english isn't great doorbell.
Just wanted to clarify since product is used for multiplying in English
And we are adding
Thank.
You.
Now leave.
ur getting invloved to much
You understand the system now?
From the picture that doorbell sent, you can try and find the answers now.
And now, find the sum of them to find the b-value.
Let me help with the first answer.
-8 + 4 = -4
The b-value of the original function is not -4
so this must not be the answer.
its not b
Yep!
is one of them c?
its c and h!!
damn
f
yesss
C and F
thats wouldve been so much quicker without doorbell
Lmao.
Bye! Np!
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help
Sea f(x) = x 2L(x) + 1. Entonces f 0 (x) = (a) 2 (b) x(2L(x) + 1) (c) 2xL(x) + Divide[1,x] (d) 2xL(x) + 3x
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How do I solve this problem? Do I plug in -1 for x?
No?
Since g(x) = -f(6x) -6
And we want the point (-1, 4)
So we could think
f(-1) = 4
So
g(x) = f(6x)
So x= -1 becomes x = -1/6
And the g(x) = -f(6x) -6 = -4 -6 = -10
So the point is (-1/6, -10)
how doess it become -1/6
then how does this become the equatiuon>>> And the g(x) = -f(6x) -6 = -4 -6 = -10
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basically its just saying
make a function for s(a)
and linearize it (with taylor polynomials) at a=0
I have s(a) = h - sqrt(h²-a²)
If I linearize it with an linearized function s1(a) = s(0) + s'(0)*a
I just get s1(a) = 0
but the solution book says s1(a) = a²/(2h)
which approaches it really good
Im surprised
but how did they even get that
they even have the same s(a) function like me
how did they approach that to a²/(2h)
man this really gets me
s(0) is 0, and s'(a) is a/[sqrt(h²-a²)] so s'(0) is also 0
Im so confused
function s (in blue), my approach (in black) at a=0, schoolbook solution (in red)
my approach fails, their approach is very close
what am I doing wrong
ok nvm, just turns out my question book is bad
if I approach it with s(a) = s(0) + s'(0)*a + s''(0) x a²/2 (which is NOT linearized)
I get that solution book answer
bad book
thanks btw
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Hello, I have a little problem, I have to calculate the domain and range of a quadratic function but I don't know how to use parentheses or brackets, could someone help me?
Just the notation.
Yes I can, but do you mean do it right now?
No that’s not necessary
So basically
Parentheses means exclusive
Brackets means inclusive
Sorry
Lemme edit
Ok.
But what means exclusive and inclusive?
Any value that x can take.
And what are those values
Real numbers?
Yes but what real numbers
For example 10.
There is one specific real number that x can’t take
I don't know, sorry.
I could say that one.
Ok
So you don’t know what an asymptote is yet
that’s ok
We can try to work around
That's right.
∞
so it's mistake?
Ohh ok.
I understand.
Ok
So x can be any value except 5?
Yes.
Can x be 5.1?
Yes.
But how can I express the domain without including the 5?
Ok.
-∞
No.
Interesting.
So when that happens
We use parentheses
So for the left endpoint of the domain
We can write (-∞
It should be (-∞
Yeah.
∞
No.
Ohhh.
So we write (-∞, ∞] because of the 5?
Ok.
So what do we do when we get really close to a number but never reach it
We use parenthesis.
Yes
So let’s read it left to right
we start at -∞
And go right
Until we hit where x can’t =
(-∞, 5)?
(5, ∞) I guess.
Yes
So
We need to join those
Whenever we have to split the domain because x can’t = something
We use U to join those fragments
U for Union
So can you write the full domain
Sorry, I have to go, maybe I'll ask that again later.
But thank you for the explanation.
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how do i set up the formula to solve this
for EB
@mystic valley Has your question been resolved?
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do you still need help?
yes
😭😭😭 I was so confused I saw my name
lol
(AE)x(EB) = (DE)x(EC)
since you only know AB, give AE an arbitrary value of
This the only Tobi thing I got rn
'x'
Anyway have fun with ur math bye
^ read this
mb
just assign either AE or EB to 'x' or any variable
ohhhh
and you know that AB + EB = 17
didn't think of that
minor typo do not set AB to x
you should
well not quite
lets just say AE is x
then x + EB = 17
so EB = 17-x
now you only have one variable
and so x(17-x) = 6(10)
and you can solve from there
dw u gain intuition from doing alot of problems
wait brb
wait what tf do i do if i get a quadratic
ohh nvm
mb im slightly dumb
you should get a quadratic
yes
its just that your two roots will be the measure of the segments
ok swag
-12 and -5
yeah -20 and 3 would multiply to -60
yea
ok 12 and 5
ok that question is done
i need help on this one
bottom one
i tried it but
can't find a way to get ED
and PB
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bru
i forgot i closed this
^
find PD first
EP is the same as PD as they are both the radius of the circle
from there just multiply PD by 2 to get ED or just add them
it's safe to assume P is the centroid?
does the symbol of the circle and the dot in the middle mean that
@mystic valley Has your question been resolved?
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@mystic valley Has your question been resolved?
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How to convert y=5 into a function of y
it's already a function of y
No, it’s y
You have to isolate the x variable on one side, so it will be a function of y
But x isn’t isolated
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Can someone answer all of this for me?
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since the initial statement isnt true
i guess its the second one
the other one
idk
i just concluded that using the initial statement
nice
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How do you do this?
do you know the curve length formula
y' is squared
oh right
wait y is the whole integral?
yes
oohh okay
then js plug that into the curve length formula
ahh okay got it ty
np
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what did i do wrong
@unreal pagoda Has your question been resolved?
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For two bases A={a1, a2, a3} and B={b1, b2, b3} in a vector space the following applies:
a1 = 2b1+b2+2b3
a2=b1+b3
a3=b1+2b2
a) What are the coordinates in base A for the vector [2; 3; 4] which is in base B?
b) What are the coordinates in base B for the vector [2; 3; 4] which is in base A?
for clarification this is how the vector [2; 3; 4] in base B is given in the actual assignment
So basically i wanna know how to convert coordinates from one base to another with the convertion equations given
i did something like this but i dont really know if this is correct at all
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How do i notate that a vector is a unit vector?
$v \cap$
ƒ(Why am. I here)=I don't Know
ƒ(Why am. I here)=I don't Know
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I need some guide/direction with question 4a how do i show that that there is no finite cyclic group with 5 generators.
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<@&286206848099549185>
Sup
Hello, kinda need help with the highlighted question here. I really have no idea where to begin with this one.
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"Determine the area A and the coordinates (µx, µy) of the center of gravity of
sector D of the ellipse if"
am i thinking right that you start with integrating x from 0 to 1 and integrate y from 0 to x?
so that A = 1/2?
Note that D is a general ellipse
So its area for example will depend on a and b
Hmm okay so I am thinking wrong?
probably
Oh okay
Why did you want to integrate x from 0 to 1?
Well I am not really sure I was looking at the conditions of D but I was thinking wrong
Do you know how to do a multivariable substitution or have you integrated in polar coordinates before for example?
We have at some point gone through multi variable substitution so I think I could do that
yeah, it's possible to do integration in elliptical coordinates and I think that would be really helpful here
So you'd have like
x = ar cos(theta)
y = br sin(theta)
etc.
Ohh okay
so like (a cos(theta), b sin(theta)) is some point on the boundary of the ellipse
and if you scale that by some let's say r between 0 and 1 you get all the points of D in a very natural way
or umm you could get all the points inside the ellipse and then by doing some additional thinking you'll also get D
one thing I'll warn you about in advance because I've done this almost exact same problem before is that you need to be very careful about the angle
because it's temping to say that the angle would be pi/4
but it's not
ohh okay thats good to know
because the theta parameter doesn't really represent an angle, it's just like a scaling parameter pretty much
Ohh I see
so really what you need is some theta such that
a cos(theta) = b sin(theta)
and that's pretty easy to solve for theta
So that we get theta = arctan(a/b)?
yeahh exactly
well if you have these (r, theta) coordinates then D in r theta land will be the rectangle [0, 1] x [0, arctan(a/b)]
Hmm okay
idk if you're familiar with that notation
Hmm not very but I think I understand
but it's like
0<=r<=1
0<=theta<=arctan(a/b)
Yeah okay
because the cross denotes a cartesian product
and a cartesian product of two intervals in R forms a rectangle in R^2
set theory shenanegans
yup that is the area of an ellipse
so you can plug that in for A
but it's not really gonna help you when you need to integrate x over the region D
but it saves you from having to integrate 1 over the region D
although it would probably be a good exercise to try to integrate 1 over D and see if you get pi * a * b
and if you do then you're probably doing something right
r*(a cos(theta))
remember that you need to be able to scale the point by r
Oh right r as well
yeah. r and theta might be slightly poor choice of symbols because r reminds us of a radius and theta reminds us of an angle but in an elliptical setting they're slightly different
Yeah that is true
I think my lecturer had like x=as cos(t) and y=bs sin(t) or something
but either way it doesn't really matter as long as you don't get confused yourself
Yeah I think r will confuse me less haha
alright then you should stick with that
Can we substitute ar cos(theta) with something?
I'm not sure if I understand your question
but I want to remind you that when you do a change of coordinates you need to remember to multiply by the absolute value of the determinant of the jacobian matrix associated with the coordinate transform
Ohh yeah right thanks
and that's how dxdy becomes drdtheta
I will continue tomorrow but thank you for the help!
Ohh okay I see
inga problem ^^ ha en bra kväll
Detsamma haha
tack
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Hey, I would like to show that a function is surjective and therefore I would like to find the codomain. Is calculating the image of the bounds enough?
I mean if the images of the bounds of the domain fits with the bounds of the codomain so is the function injective?
You have to show that f^-1(y) exists in the domain for each y in Im(f)
Or that codomain equals image
You mean f: [a,b] → Y and you calculated f(a), f(b)?
Okay so for example to show that cosh(x) is bijective de R+ on [1 ; infinity[, I can just find cosh(0) and lim x->infinity cosh(x)?
Yes
This implies injectivity only if f is continuous and strictly monotonic
Ok so if the function is continous and stricly monotonic, I can just calc f(a) and f(b)?
Why it has to be strictly monotonic?
If it isn't strictly monotonic then f(a) = f(x) for x > a is possible
And so it isn't injective
Ah yes of course
But if I want to show that f is surjective I can just calc f(a) and f(b) and see if it fits with the codomain right?
Or it has to be continous
and monotonic
I am not sure. Showing that f^-1(y) always exists is 100% enough
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Hello
Can someone help me in factorising please.
post your question
As Im doing Vector Geometry and I just dont know how to factorise.
Ill send now,
=6/4b+3/4a
I learnt this but I completely forgot
I know it equals 3/4(2b+a)
but is there like a method I can use to get there
and not my common sense
because there are harder ones
or is it just how many eg, on the question I sent how many a's go into b
@faint forum Has your question been resolved?
@faint forum Has your question been resolved?
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I don't understand letter A and B for the graph.
I get that it is an infinite limit where in part A, x is approaching -infinity and you have to see what f(x) equals but from what I got as an answer versus what I was told the answer was are two totally different things. To me it looks like where x is approaching -infinity, f(x) = 1, but my professor said the answer to that one was -5. For part B, to me it looks like x is approaching infinity at f(x) = 0 but she said it was 2. That is all that I know so far and why it is not making sense.
can you circle / indicate which part of the graph you're looking at for each part
your prof is also wrong for part a)
yea so for part A for example, I am looking at the middle line where it seems to be approaching -infinity, when looking at which x coordinate that is, it seems to be 1. for part B, i am looking at the left-most line where it is approaching infinity, by looking at the corresponding x coordinate for that, it is 0.
please circle/mark the location on the graph
you're looking at the wrong places
where should i be looking?
where x→-inf, x→inf
you're looking around where x is 0 and 1
you should be considering what is happening as the graph:
extends to the left
extends externds to the right
okay so i should be looking here instead for the first one because its like a book (reading it left to right)...
-5
no
no
0
yes
since its on the axis
so the limit x approaches -infinity at 0? and for the second one, the limit x approaches infinity at 5?
no
and wrong wording
as x approaches -inf, f(x) approaches 0
$\lim_{x\to -\infty}f(x) = 0$
ℝαμΩℕωⅤ
how are you getting 5 for the other limit?
that makes sense, yes.
again it seems like you're looking at the wrong value
you're after the y value the curve approaches
i was getting 5 for the other limit because i was looking at the first line where it was curving up and going to infinity. the closest value to that on the y axis was 5. but maybe I should have been looking at the third line where x approaches infinity it is at the HA of 2.
the difference being y approaches infinity on the first line when it curves up, not x
does that sound correct?
wdym first line
oh,
yeh
for x→inf, you're interested on what's happening way over on the right side
yea, so the green line is the first line i was talking about, the orange is the third line i was talking about
so it should be:
x->-inf f(x)= 0
x->inf f(x)= 2
yes
i think thats where i was getting confused was with where to look and me looking at where y was going infinity or -infinity rather than x
thanks so much!
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The distance from points A and B to l line is 20cm and 16cm. Need to find the distance from AB lines middle point to the l line
@rain hollow Has your question been resolved?
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Use L'Hospital
Maybe devide up and down with 2x
It would be nice to have everything in terms of sinx
You get more manageable limits


