#help-13
1 messages · Page 107 of 1
what's the goal?
it is correct yes
why in blazes would you expand
you can factor a lot of shit out
as is
without busting your ass expanding only to then get stuck with a hard factorization
x^2 + x = x(x+1)
(2x-4)^2 = 4(x-2)^2
well i don't know, are you allowed to rewrite (x^2+x)^3 as (x(x+1))^3?
$(a\cdot b)^c = a^c \cdot b^c$
kheerii
use laws of exponents
on the top you have 4 x^3 (x+1)^3 (x-2)^2, from which you care only that it behaves as 4x^8
on the bottom you have x^7 * sqrt(4x^2 + 2), and squinting at sqrt(4x^2 + 2) turns it into sqrt(4x^2), or -2x (because x is approaching negative infinity)
this would help me?
everything is in it's own jail cell, so to speak, with the brackets
hard to cancel anything out
I need to get some of these terms out of the brackets in order to cancel them, right?
or is that not the goal here, just start to evaluate where x is -Inf?
you can figure out how the function behaves near the limiting case
i.e what the apparent degree of the numerator and denominator is
so the odd powers will keep it -Inf, the even powers will make it +Inf
hmmm, so with the denominator I believe it would be power 8
the numerator power 5
oh it's 6 * 2?
dont get what you mean here
numerator is power 12?
why *
right
in most cases, the degree of the numerator and denominator should be the same
right
interesting
so this tells me that it will have to be POSITIVE
even powers
it's like saying +Inf/+Inf?
nope
oh
this is wrong
how so?
what would be the coefficient of x^8 in the numerator
nope
1?
its the coefficient of the highest power term, ya?
if it's not 1 or 2, then no clue
how did you get 1
this
yeah
but
why would it be 1
but you
x has a coefficient of 1
have to multiply it with the terms of the other multiplicant
but i already said 2, and that's wrong?
remember this
2
imagine reading what i wrote 
sqrt(4)
couldnt be me
i don't understand this
and you didn't think to ask until now?
square roots are defined to be strictly positive
if i add my own sqrt i would have to use +-
but since it's already included it's just implied as +
what?
ONLY when they are written for you
not when you write them yourself
if you add a sqrt out of nowhere
like sqrt(4)
the answer is not just +2
it's +- 2
???
sqrt(4) is always equal to +2
that's what I said
square roots are strictly positive
"evaluate sqrt(4)" is a different problem than "solve the equation t^2 = 4 for t"
sqrt() always returns the positive solution, and it is your job to account for the negative root too IF CONTEXT CALLS FOR IT
which here it does not.
what do you mean by that
where it's not already included in the question
in this case it's already included
so it's just +
but if YOU add your own sqrt
no
you gotta account for +-
???
no matter how you introduce a square root, whether it's already there or if you add it
misconception time huh.
sqrt(x) ALWAYS represents the positive value
this is exactly how professor leonard taught it
$t = \sqrt{4} \implies t = 2
t^2 = 4 \implies t = \pm \sqrt{4} = \pm 2$
whenever you have an even power, that's where the plus minus shows up
kheerii
Support: https://www.patreon.com/ProfessorLeonard
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How to solve quadratic equations with the Square Root Method.
oh that wording is yuck for PRECISELY the reason that we're running up against here.
agreed
this "always put a \pm in front of your sqrts" is a crutch that eventually breaks
what doesnt break is the knowledge that $\sqrt{x^2} = |x|$
Ann
did you even bother to read what I wrote?
oh well yeah
sqrt(x^2) = |x|
this is the one exception
but for everything else, i think
even power roots, if YOU add it to the paper yourself, you gotta add +- in front of it?
just like professor leonard stated
the plus minus is completely disconnected to the square root sign
the square root is still returning a positive value
$(...)^2 = a^2 \implies (...) = \pm a$
kheerii
right i understand that, i'm saying IN FRONT of the sqrt, add +-
like how professor leonard shows it in the timestamp
you can justify this by saying
$(...)^2 = a^2 \implies (...)^2 - a^2 = 0 \implies ((...)+a)((...)-a) = 0 \implies (...) = a, (...) = -a$
kheerii
kheerii im so sorry but i have to delegate this entirely to you for the sake of my own sanity
it's alright lol
you don't wanna put +- inside a sqrt, otherwise you would be getting complex solutions
I don't know if that's what you were implying with this
here you have +-
so we agree
$(...)^2 = a^2 \implies (...) = \pm \sqrt{a^2} = \pm |a|$
kheerii
the modulus is unnecessary here, I just put that for your clarity
a is not a variable? a is a constant?
both ... and a can be absolutely anything
an algebraic expression
a
number
anything
why the pipes?
you said unnecessary, just wondering why they were added
...pipes?
i added them because technically sqrt(a^2) = |a|
but the +- negates the modulus anyway
but you stated this
sqrt(a^2) = |a|
sqrt(4) = |2| ?
ummmm
sqrt(anything) >= 0
so where is the +-?
im getting to that.
ok
@marsh pond stop rapid-fire replying... read and think about it
make sure you are really comfortable with this
yes, the domain of even roots must be [0, Inf)
correct
now
about the plus minus
whenever you have an even power in a polynomial, that's when the plus minus shows up
the simplest example is x^2 = a^2
this is where your point of (2)(2) = (-2)(-2) = 4 comes into play.
$x^2 = a^2 \implies x = \pm\sqrt{a^2} = x = \pm |a| = \pm a$
does this make sense to you?
the plus-minus sign is completely disconnected to the square root
wait, let me make it more clear
kheerii
you are taking sqrt(a^2) = +-a
oh right
the plus minus only shows up because of the even power of x
to write what
this is just factually incorrect
this is right
isn't that what professor leonard is stating in the timestamp?
i don't understand where his wording is incorrect
whenever you have squares on both sides, THAT'S when the plus-minus shows up
the square root does not inherently have anything to do with plus-minus
and I have repeated this like 5 times atp
professor leonard states "whenever YOU add an even root to the paper, you must include +- in front of it"
but you are saying this fails for x^2
sqrt(x^2) = |x|
yes, because the way he says it is VERY bad wording
would this be the only scenario where +- is not needed in front of even root?
and that's why you are so confused
yes
but it's still good to know
when dealing with even roots
you gotta account for +-
unless it's just a variable? i guess
such as x^2?
what about sqrt(x^2 + 3)
always positive
the simplest way to remember it is the same two equations I have been repeating for the past 20 minutes.
$sqrt{a^2} = |a|$
kheerii
what about sqrt(x^2 - 3)?
and, $(...)^2 = (a)^2 \implies (...) = \pm a$
kheerii
it's always positive.
but what if x is 1
then the square root is not defined in the reals anyway
and if you're including complex numbers, all the rules go out the window
but it's still positive?
the square root is not defined.
oh
we go into third dimension
z axis
complex realm
anyways
i haven't learned about that so i won't bother asking yet
what you just said was very wrong but
let's just move on
i HOPE you've understood what i am trying to tell you now.
tbh, it probably adds more confusion (sorry)
I thought +- needed to be added in front of even roots, if I write them on paper
I thought just + is implied, if even root is already included on paper
and i thought sqrt(x^2) = |x|
they did tell you that
i never see it written like this, except for x^2
oi
yes
and now 2 is treated like a piecewise function?
|2| =
2 if 2 >= 0
-2 if 2 < 0
lol
I do realize this doesn't make sense, but just trying to understand the next piece of logic after sqrt(4) = |2|
for sqrt(x^2) I can certainly see this as a piecewise, defined above
as x is a variable and can change signs
-2 if 2 < 0 but this is where the logic fails for constants
https://math.stackexchange.com/questions/225388/why-sqrt4-isnt-equall-to-2 taken from this page
I still don't see the issue with what Professor Leonard is saying here
"plus or minus in front of the square root of your CONSTANT"
this is correct
he didn't say "plus or minus in front of the square root of your variable"
@tropic oxide fyi
$\sqrt{4} = 2$ is just convention in most cases
|2| is just two
is reserved for the positive square root
riemann
It's just in place to tell you that the square root of a positive real number is always positive
this piecewise only makes sense because x can be negative a priori. you've already ruled that case out by setting x=2
i don't even understand why you're arguing over this semantics. you're supposed to do calculus, not basic high school algebra.
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these questions give me migraines 
i think i got the answer but i need a confirmation
a=0,b=-2?
<@&286206848099549185>
how'd you get the answer?
Btw can you multiply X^(ab) both sides? Idk coz x^ab may be negative as well but you know- exponential functions a^x>0
and your answer is wrong FYI
,tex .exp rules
riemann
X^a^2 / X^(ab) can be written as X^(a²-ab).
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I miht be interpretting this wrong, but im confused on how they got the new height of triangle A’B’C’ to be 10 instead of 12 - root(3)
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dont judge i beg
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What step are you on?
1. I don't know where to begin
2. I have begun but got stuck midway
3. I got an answer but I'm told it's wrong
4. I got an answer and would like my work checked
5. I have a question about someone else's worked solution
6. None of the above
3
Show your work, and if possible, explain where you are stuck.
i didnt write my work
What's the x = -1 mean?
Do you know what m and c means?
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Hi, I'm having trouble solving a problem, In this task I have to calculate the ratio a:b if this calculation = 6dB.
10lg(a/b) = 6
lg(a/b) = 0.6
That's just dividing both sides by 10
Then raise both sides by 10^ to get rid of the log
In the solution book it says 3,98.
I was translating the problem because the original problem is in German and I'm not sure if ratio is the correct translation (in German it says "Verhältniss")
I first tought the solution to the problem would be something in the way of 2:5 or 6:1
This problem has more smaller parts to it where the change is the number coming out of the calculation[calc...calculation] (6 was for sub problem b) ). Others are for calc. =1 solution 1 ; calc. = 9 solution 7,94 (or 8 if you round what seems tho be wanted guessing from how the solutions do it as well).
@upper abyss do you happen to have another idea how this could work?
@south oracle Has your question been resolved?
<@&286206848099549185>
I found out how it works, not really sure why it works like that. I`ll ask my teacher if he could explain it to me.
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I need help simplifying this horrible expression, anyone got any tips?
d,q,l,i,t,E ∈ ℝ+
Idealy I would like to get rid of the square root if possible
@karmic palm Has your question been resolved?
is "lit" a term on its own, or are l, i and t separate ?
l,i,t are separate
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I just have a question
I will try to translate
So we have a<b and delta is a partition of [a,b] interval
P(delta) is the set of all sample points for the partition delta
And f:[a,b]->R is a function
We say sigma(f,delta,c) is the Riemann sum for function f, partition delta and the sample points c.
At a) it says that: if f has Darboux Propriety then we want to show that I(delta)={sigma(f,delta,c) | c in P(delta)} is a interval
Can someone explain me what that I(delta) exactly means?
Isnt the set of all riemann sums for function f, for a fixed partition delta and all sets of sample points for the partition delta?
I dont understand how a set of riemann sums can be an interval?
<@&286206848099549185>
@crimson sedge Has your question been resolved?
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$2(10)^{x+2}=35$
putridplanet
Id divide by 2 coz fuck it
answer sheet says log 35/2 -2
Yeah, I forgor to divide by 2
minus 2
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was wondering how to solve this equation
ive forgotten the process of how to make sure theyre to the same log
$\log_{5}{x} = \frac{\log{x}}{\log{5}}$
Kookiemon
do that with both of the logs
i think one time someone said something like sub in a random value
like on both sides?
mhm
yes
but at this point what do i do
divide 16 onto the other side but then
its just on the other side
this is something = 16/something
can you solve for something
then you know what logx/log5 is
log(5)/log(x) = 1/(log(x)/log(5))
$16\frac{log5}{logx} = \frac{16}{\frac{logx}{log5}}$
zfnQRZJT
ahhh i have got another method to trying this
just then
i found its a bit easier however
when i get to the last stage
i’m wondering would i just use guess and check
5=x^(1/4)
there is an easy way
take both sides to the power of 4
or -4
that isolates x
i feel a little stupid
WHY DIDNT I GET THAT SOONER AGHHH
thank you though
i really appreciate the help
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How would i go about finding "y" so it satisfies both scenarios? Or how would i find a pair of x and y that satisfies both?
x = 20
y = ?
0.068 = (y(dx997)) /((x1000)+(dx997))
14.8 = (x(dy997)) / ((y1000) + (dy997))
If i replace for the above i get: 1.4 (x = 20, dx = 1)
For the bellow i get: 0.35 (x = 20, dy = 1)
Id like to find a balance between x and y for them to satisfy both outcomes, how would i calculate this?
@ionic nimbus Has your question been resolved?
Some examples of it working:
x = 691
y = 46
x = 2593
y = 173
How could i write an equation to get to these?
@ionic nimbus Has your question been resolved?
do \ * instead of *
cant read that properly
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why does this work?
like I do not understand the mark scheme.
but i get confused
@bronze scroll Has your question been resolved?
<@&286206848099549185>
.
sorry I got
3 roots
so
(x-2+i) and (x-2-i) and (x+1)(x-2) four I mean
but I do not know where the (x-2)^2 comes from
i mean i know i am left 1 because n^5 but still why is (x-2) the repeated one?
because of tangency
??
,w plot (x+1)(x-2)^2
when you have a double (or more) root it is tangent to the x axis
like here, the graph is tangent to the axis at x=2
dy.dx = 0
yeah
but why like how do you know it is repeated life if i see a min on that point in x
do i just know that it is (x-2)^2?
if its on the x axis
is there any video on this topic?
and its a polynomial
Keep going! Check out the next lesson and practice what you’re learning:
https://www.khanacademy.org/math/algebra2/x2ec2f6f830c9fb89:poly-graphs/x2ec2f6f830c9fb89:poly-intervals/v/polynomial-multiplicity-examples
The polynomial p(x)=(x-1)(x-3)² is a 3rd degree polynomial, but it has only 2 distinct zeros. This is because the zero x=3, which is ...
ok thanks
np
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what's the goal here
This is the question i have to simplify it
How to solve inverse trigonometric functions
uh ok so like. you should always post the whole problem lmao
arccos(sqrt(2/3)) + arccos(sqrt(3/8)) could probably be rewritten as the arcsin or arccos of one angle
arccos(sqrt(2/3)) + arccos(sqrt(3/8)) can prob be expressed as arcsin or arccos of one number
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working on a problem about dilations and enlargements and i'm confused because i have no other idea of what it could be. because if the preimage is scaled by 3 and the area of the preimage was 4 shouldn't it be 12?
when you scale something up by 3 its area does not multiply by 3 but by 3^2
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✅
thank you
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this is the original problem. i pretty much figured it out. but i ran into something weird when i was optimizing. i arrived at a distance formula of d = x^2 - x - 2 and calculating the first derivative of that distance as d' = 2x - 1, but this was wrong. putting it into desmos, desmos calculates a derivative of d' = 1 - 2x. how did i mess that up?
this essentially inverted my derivative, showing me an absolute min at x = 1/2 rather than the absolute max that it is.
like this it doesn't look right though. so i added the absolute value to the distance since a distance can't be negative
giving this
which is the proper output i would expect. how does the absolute value affect the derivative in such a way?
derivative of $x^{2} - x - 2 \neq |x^{2} - x - 2|$
! saad
2x-1 
$\frac {dy}{dx} |x| = \frac {x}{|x|}$
! saad
so in effect, how should i have gone about this?
formula is $\frac {dy}{dx} |f(x)| = \frac {f(x)}{|f(x)|} \cdot f'(x)$
! saad
because using the first derivative test on 2x - 1 gives an abs min rather than a max
that definitely works
was it the right choice to think of using the absolute value since this is a distance? the graph looks way better that way, and doesn't give an absolute min by the first deriv test
You got the right answer so everyone should assume so
If it ain't broke don't fix it
absolute value is correct, find the maximum for the absolute value function
just threw me for a loop thats all. thought i had it right and then when i graphed it in desmos it looked messed up until i used abs value. i guess i gotta memorize that derivative
thanks guys
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How would I draw this?
would it look like a rhombus or something or do i just wing it
do you have to draw to scale
no
I would say draw a generic quadrilateral
but all the sides are unequal
don't even bother making the sides the correct ratios
unless it matters, like, which side of a line a point is on
totally wing it
so i can just draw a rectangle
pretty much
this is a rectangle
yes
or rather looks like one
you might be better off drawing it to not look like a rectangle
what should it look like then
just a generic quadrilateral

you sure can.
AC = 11.94cm
sounds approximately right
i also found angle A from DAC to be 53.84 degrees
hmm
nyeh?
you know sqrt exists and is understood by desmos right
show work
if only to ensure no stupid arithmetic mistakes happen
you found angle ACD not angle DAC
huh
the sides in the denominator, and the sides whose squares are added in the numerator, are those between which the angle is.
the third side's square is subtracted in the numerator and absent from the denominator.
so it's a case of misidentifying which side goes where and as a result calculating the wrong angle.
so i subtracted and added the wrong sides?
yes that's what i said
actually i should label A as C
@tropic oxide Did I add and subtract the correct sides?
... okay hold on you swapped the letters
yeah
so it appears.
could do that, sure.
it's a little bit unkosher to shuffle around point names like you've done, tbh.
not every triangle you come across will be named ABC.
well i guess i could always change up the letters
it just makes it easier for me to understand
no the thing is
you'll be using the point names in ways that conflict with how the original problem uses them
your B and their B won't be the same point.
i would recommend that you not risk such confusion.
its just using the point names that the problems uses ex ABD kinda confuses the formula up for me and swapping the values around
and this is why i suggested you understand the formula in a name-free manner.
an angle has two adjacent sides and one opposite side. to find the cosine of your angle, you take:
the sum of the squares of adjacent sides minus the square of the opposite,
all divided by 2 times the product of the adjacent sides
by two adjacent sides ur talking about the hypotenuse as well right?
i am talking about the two sides that border your angle
okay
@nova snow Has your question been resolved?
it's an area
is length OA also 4cm
it looks like it would be equal
is the circle just there to be confusing
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In a right triangular prism and in a orthogonal frame of reference as well as Oxyz monometer, it's known that:
Point A (4 ; 4 ; 0)
Point B ( 2; 2; 4)
the vector OC is (-2 ; 2; 0)
» Find the angle formed by the vectors BC and BA
» Using the dot product, find an equation that can define the spherical surface of diameter [BD]
» Determine a general equation of the plane perpendicular to the line OC and containing the point B.
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@tropic oxide are you able to help me out when you have some time?
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Can some one solve it for me?
Thank you
!show
Show your work, and if possible, explain where you are stuck.
have you tried anything
no one solves it for you, someone can only guide you
yeah help me
very hard question
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it says the first step is putting AD in terms of h. have you made any progress on that?
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,tex \left. \begin{cases} { A = \left(\begin{matrix} 2 & -1 \-1 & 2 \end{matrix}\right) } \ { { A }^{ 2 } -4A-n \left(\begin{matrix} 1 & 0 \0 & 1 \end{matrix}\right) } \end{cases} \right.
sarang
Compile Error! Click the
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(You may edit your message to recompile.)
can anyone help me with this
whenever i try thos
i do not get a diagonal matrix after
A^2 - 4A
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what's your result?
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the channel timed out! you might need to get a new one.
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need help on 4
not sure what my common ratio is
Note that $\sin\theta - \frac13\sin2\theta + \frac19\sin3\theta - \frac1{27}\sin4\theta + \dots = \ = \Im((\cos\theta + i\sin\theta) - \frac13(\cos2\theta + i\sin2\theta) + \frac19(\cos3\theta + i\sin3\theta) - \frac1{27}(\cos4\theta + i\sin4\theta) + \dots)$
A Lonely Bean
Can you apply the Euler's formula here?
Yeah, and you will notice that it becomes a geometric series
yeah thank u
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could someone help me with #11
Do you know what a mole is?
isn’t it something to do with 6.02 * 10^23
@inland ocean
do i divide 7.5 x 10^23 by 6.02 * 10^23?
cause then i got 1.25 (rounded)
but then what am i supposed to do
Yeah it seems correct
I was confused what they meant by formula units
Ig it's just the no. Of molecules
so is it 1.2?
,w 7.5/6.022
Yeah
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Can somebody help me with my understanding of the chain rule?
the formula i was given seems to be both the chain rule and the power rule simultaneously
this video is excellent for it https://youtu.be/YG15m2VwSjA
A visual explanation of what the chain rule and product rule are, and why they are true.
Help fund future projects: https://www.patreon.com/3blue1brown
This video was sponsored by Brilliant: https://brilliant.org/3b1b
An equally valuable form of support is to simply share some of the videos.
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what's the formula you're given?
df/dx = df/dg * dg/dx
is easy to remember
I will write it out real quick
i'm familiar with this and am able to use it
but is this not the power rule and the chain rule simultaneously?
it is both
you can also get that with product rule only and induction but yeah
well, i have to use other forms of derivation and then multiply by derivative of inner function
and it just seemed strange to me that two completely different looking derivatives were both being described as "chain rule"
my confusion basically lies in the fact that I was taught the chain rule as a formula where it was only being used in addition to the power rule
ah
i was simply told, chain rule is this:
and sort of found out myself that i can do it to non-exponent parts of an equation
they didnt teach it as f(g(x)) ‘ = f’(g(x))g’(x)?
This is a very specific version of the chain rule
In this case the "outer" function is x^n, and the "inner" function is f(x)
nope, just the specific version of where it applied to the power rule
weirdddd
so basically i've just sort of adopted the strategy of
derivate the outer function as if it just said X and then retain all the original inside parts of the outer function
then multiply by derivative of inner function
which i sort of see as the same thing as this now
well, this was helpful, thanks guys
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hi, can someone help me with this double integral question pls. Tried and didnt get the same ans as the calculator
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ideas on where to start?
maybe split them into their fractions
Write everything in terms of sin and cos
^^
(1+cosx)/sin(x)
————————
(Sinx/cosx) + sinx
try simplify that
(1+cosx)/sinx * (cosx +cosxsinx)/sinx ?
keep going and see if u get the answer
Uhh I’m at (cosx(2x))/(sin(2x)), how would I use the double angle identity for cosx(2x)
how did you get cosx(2x)
Multiplied this out
Then factored a cosx
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hey
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I'm stuck on 2
so if A is independent the scalars must all add up to 0
aka the scalars are all 0
c1,c2,c3,c4 in F
now i'm not quite sure how to go about this now
Well occupy a different channel , since i can't now
oh lmfao
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Let $a,b,c$ be the roots of $x^3-9x^2+11x-1=0,$ and let $s = \sqrt{a} + \sqrt{b} + \sqrt{c}.$ Find $s^4 - 18s^2 - 9s.$ (Source: HMMT)
FireBlazer
im pretty sure Vieta is needed but not sure how it comes in
@static fern Has your question been resolved?
@heady spindle this channel is occupied.
sorry sorry I don't see
its ok
find s²
first
@static fern
$s^2=a+b+c+2(√ab+√bc+√ac)$
with Vieta's formulas we can say that $a+b+c=9$
to find $2(√ab+√bc+√ac)$ we can square it which makes $ab+bc+ac+2√abc(√a+√b+√c)$, and we can find $ab+bc+ac=11$ and $2√abc(√a+√b+√c) = 21s$
Ozgr
so $(√ab+√bc+√ac)^2=2s+11$
Ozgr
which makes $s^2=9+2√(2s+11)$
Ozgr
$s^2-9=2√(2s+11)$
Ozgr
by squaring both sides $s^4-18s^2+81=8s+44$
Ozgr
$s^4-18s^2-8s=-37$
Ozgr
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I may be blanking but I'm having problems evaluating this..
Why is change in x^2 + change in y^2 sqrt equal to speed
I have this so far:
Lol
blanket
Yeah, I have two negatives though.
right
subtracting a negative is the same thing as adding it
Yeah, a +
then you just simplify what you have?
there's nothing else to it if k is just a constant
The answer is supposed to be 3/4k but like..I’m not getting that?
$-\frac k4 + \frac k1 = -\frac k4 + \frac{4k}{4}$
blanket
not necessarily intuition
to add fractions with no common denominator, you just multiply something on the top and bottom :)
Thank you. May I ask a question on integration? It's related to this problem..
yeah sure
I'm still a little confused on the steps of integration for a function like k/x^2..
so they pull a constant k out
right
we get k* integral of 1/x^2
but I thought that should turn to x^-2...
I must be confusing it with something else
thats taking the derivative
oh
yep
you're taking the anti derivative of k/x^2
actually, a revision to my old statement, you'r enot taking the derivative if k/x^2 turns into 1/x^2
you just magically removed the constant
the derivative of that would be -2k/x^3 i think
im just not sure what happened there
Yeah, in that case it becomes -1/x, but what's the step using the power rule for this? Don't we add 1 so it becomes 1/x^3 and then divide by 3 so its 1/x^3/3?
blanket
Oh, so because its in denominator we remember to treat it as 1/x^-2....and then apply power rule?
no
$\frac{1}{x^2} = x^{-2}$
blanket
so $\int_1^4\frac{k}{x^2}dx = \int_1^4 kx^{-2}dx$
blanket
also unfortunately i do have to go now
<@&286206848099549185> if they still need help
ok

no dx or dk
answer is infinity for k =/= 0 gg ez
sure
So this is supposed to be straight forward but the functions my professor is giving is seriously difficult to work with
for context...
Our p(x) was given as k/x^2
and our k is 4/3
uh huh
but like, I'm stuck on trying to evaluate x(4/3/x^2)dx...
Got it, not sure what I was thinking..We now have integral from 1 to 4 of 4/3x, we take the 4/3 out and get 4/3* integral 1 to 4 of 1/x, and then we take the integral of 1/x and get 4/3* integral 1 to 4 of ln|x|?
4/3 * ln(4) - ln(1)
My final question is on this...does it seem like I'm on the right track:
im ending up with 4/3*-1/x, where I will be plugging in m and 1
@elder elm Has your question been resolved?
I’m getting -8/11..
<@&286206848099549185> Can anyone help me understand what I did wrong?
@elder elm Has your question been resolved?
Oh wait so its supposed to be addition because we should have a minus symbol and the value is negative?
ye
I'm still ending up with incorrect value...I'm getting 30/15...
1/2 = -4/(3m) + 4/3
-4/(3m) = 3/6 - 8/6 = -5/6
Wrong picture
I’m now getting 30/15..
4*6 = 24
oh snap
it's always the arithmetic that gets you (not you specifically ppl in general)
never the hard math
/joke
awesome!
yeah seems like somethings going wrong with my arithmetic..
Could you help me understand this?
I do not understand how they got e^5k=305/330=61/66..
hey lost me at this part. But I understand everything up to y(t)=70+33oe^kt
given the initial condition y(5)=375, they substitute this into the equation to solve for "k".
replace y(t) with 375, and replace t with 5
and then solve for k, as they did
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Is $|\lim_{x\to x_0} f(x)| = \lim_{x\to x_0} |f(x)|$?
Frosst
What if the first one exists
The question is show if $\lim_{x\to x_0} f(x)=A$, then $\lim_{x\to x_0} |f(x)| = |A|$
Frosst
I’m pretty sure I’m supposed to use limit definitions but I want to see if this other way works as wel
if f is continuous at the point, then yes it's true
Does it work at all if it’s not continuous? Like via the limit def
if it's continuous at the point x0 it should work. because you basically have a neighborhood of continuity around x0 in that case.
if it's not continuous at x0 then you just have a bunch of 'does not exist' statements, where equality doesn't make sense anyway
but you should be able to get this without the limit definition
that seems like overkill, imo
That’s what my teacher implied is used for the solution pdf
But I suppose since it doesn’t explicit say to use the limit def this should do
Now that I think about it it seems just like a composition of limits
And limits of composition
Aight thanks
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