#help-38
1 messages · Page 198 of 1
do i need to solve it or use it somewhere else to figure out another angle
can you find 180-KLC from that?
YES
Now, the next is the most critical step for this problem
Join the points K and B
now what can you say about KLB and KAB triangles
they are the same right?
proof?
uh
each of them has one y side
and 1 x side
im not sure if thats how you do it
oh wait nvm
because angle BLK is 2z
and thats not the same
Do you know congruence of triangles?
no
Like can you name the tests for congruency?
not entirely
isnt it like when there is 2 triangle
and they are proportional
in angle
proportional is similarity
oh
yeah idk congruence tests
Congruence is like 8th grade maths. you sure about that you dont know it?
no
im just now in grade 8
how do you find out if something is congruent
theres test for congruence
like if all three sides are same, then all the properties of the triangles are the same
oh
or if two sides and the angle between the two side is same, then also all the properties are same
Yea, somewhat. Bu you only talked ablut 2 sides. So thats not sufficient
i talked about 3
But yea
thats the point. The twi triangles are congruent
wait
only from 2 sides?
coz the 3rd side is the common side so its also the same
ohh
yeah
so that means
CAB=BLK
That means the angles KAB and angle KLB are equal
mhm
yep
5/2a
=180
5a=360
a=72
or so
and since top angle is 1/2a
ITS 32
36
YES
I GOTIT
tysm

yea lol
yea
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Can someone tell me why the bottom one is right and the top one is wrong. And why on other questions both methods work?
,rotate
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$x(x+h)\neq x^2+h$
CST (reply ping for help)
oh yea
am i allowed to factor out h from that top fraction in the 2nd last step the way i did
ussualy yes
Oh please put lim_(h->0) everywhere
but this time you removed the h from x^2+h
yes but you need to still multiply x by h at x^2+x it should be x^2+x*h
so it should be like this?
yes
now you just need to "take"/"solve"/"complete" the limit
what
When h = 0 ,xh = 0 leaving -2/x^2
remove the h
isnt that what i had before anyway
!noans
The purpose of this server is to help you learn, not to hand out answers. Do not ask someone to give you the answer directly.
-2/x^2
in this
yeah you can get the right answer for the wrong reasons
fair enough
does it matter if the derivative function i get is a rational function like this
questions that ive done for this stuff before usually give a linear function
No
You can do -2/x^2 or -2x^(-2)
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how would i go about finding y, i believe i found x correctly, i used tan inverse and got 29.74 degrees
Angle sum of a quadrilateral = 360 deg
so would i minus x from 360 to find y?
What about the two right angles?
and those
then yeah
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could someone help explain why the answer is d
im going to upload my work in a sec
ok here it is
so i managed to factor it into this form
i just set x=log2x
sorry if thats confusing
Make sure to keep a table of log identities nearby as you work
,tex .log rules
riemann
I'm not sure why they use f(x) when they just mean "log2", maybe to trip you up? It doesn't really do much
You just want to simplify. You'll get one of the answers
I did x^2/4x to get log2(x/4) and then multiplied by 8 but that gave me log2(2x)
log2(2x)
= log2(2) + log2(x)
= 1 + log2(x)
You're good haha, almost there
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gauss plane and argand plane refer to the same thing?
I know it as Argand plane, the plane that has like x = Re(z) and y = Im(z)
x-axis and y-axis respectively I mean
yes
Wikipedia says that Gauss plane is another name for the Argand plane
but I've never heard of it being called the Gauss plane
the most common term in English is just the complex plane
exactly my thoughts until I saw a maessage in #math-pedagogy
translated from their own language, lol
I appreciate the help, no need to create more work for u guys, I can actually google this, sorry for this
thanks
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I’m stuck at this question:
“Imagine you throw a bouncing ball at a train. You throw the ball at a speed of 20 m/s directly towards the train, which is moving at a speed of 180 km/h towards you. What speed does the ball have if we assume the bounce is perfectly elastic?”
I checked and the solution in the answer key is:
“v_train = 180 km/h = 50 m/s
The direction of the train's movement is the positive direction.
Towards the train, we imagine a thrown ball with
a velocity of v_ball before = -20 m/s (negative direction).
We are looking for the ball's velocity after the bounce towards the train and call it v_ball after. The train's velocity after the bounce is still
50 m/s. The train's velocity is hardly affected by a small ball hitting it.
The bounce is perfectly elastic. The following equation holds:
v_ball after - v_train = v_train - v_ball before
v_ball after - 50 = 50 - (-20)
v_ball after = 120 m/s (432 km/h)
Answer: 120 m/s"
I don’t really understand how the solution arrived at that answer. I tried using the formula: mAvA1 + mBvB1 = mAvA2 + mBvB2. I thought that the mass in this case should be irrelevant, so I wrote it as:
-20 + 50 = x + 50
-20 = x
Answer: The ball's speed is -20 m/s. (Incorrect answer)
How should I have solved the problem instead? Am I using the wrong formula, and if so, which formula should I have used?
@clear ember Has your question been resolved?
<@&286206848099549185>
,w 180kmph to m/s
Yea I think so?
wouldnt the velocity of the ball be -70m/s?
Ok if you’re on the train
The ball comes at you at 20 + 50 m/s
This means from the perspective of the train it should bounce and go forwards (away from the train) at 70 m/s
my english is not englishing, where is the ball thrown from?
But you’re on the train that’s also moving at 70m/s so from a stationary observer the ball would be moving 70m/s + 50m/s of the train’s frame of reference
So 120m/s in total
are you throwing the ball at the train while you being inside the train or outside the train?
my english level is very poor
As I understood the text I am trowing the ball on the train from the outside but yea it's a bit unclear so I might be on the train?
No the ball is thrown from stationary towards the train
So I'm on the train then? Sorry I am quite lost lol
Alright!
If I'm supposed to use this formula then why do they switch to - instead of using + in the answer?
This I don’t think is right
This assumes that the bounce will take kinetic energy away from the train
Alright so what formula am I supposed to use?
Alright thanks!
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Can someone see for me if my working for part B is correct?
No the tangent is a straight line
Sub x=4 into the derivative function to find the slope of the tangent
Before using point line formula
you mean x = 4
Oh yea
yeah it's $y - 2 = f'(4) (x - 4)$
south
Oh okay thank you
no worries!
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i'm not sure how to deal with my a.b term here
i cropped it out but p = λa + (1-λ)b (or so i think)
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ive done a b c
for d do they want me to use 3-13x to find 2.9998^6?
im kind of confused
also for c does my value of x seem to be a suitable value
i dont know which expansion they want me to use from
i assumed the original one from a
you shouldn't have done those last two lines in a)
if you want to factor out a value, indicate it as such instead of just dividing
you x value is fine
oh i only did it because in the question it asked for the simplest form
the point still stands
729 isn't the same as 3 etc
whether the factored form or standard form is considered simpler is a different matter
in this case, they probably want expanded
so for a) should i have just left it like that without dividing it?
yes
but
if you want to factor out a value, indicate it as such instead of just dividing
wdym indicate it as such
ah
also 36/3 is 12, not 13
yes
yes
so 729-2916x=2.9998^6?
not = and not quite
729 - 2916x when x=0.0001 (the value you found in c)
will give an approximation of 2.9998^6
i got 728.7084
,w 729 - 2916x when x=0.0001
that should be right then cause they asked for 4 dp
alright thank you for the help
,calc 2.9998^6
Result:
728.70844859568
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Can someone help me with this?
I understood the part where sad face means subset relation and smiley face means set equality
I just cant understand the idea of x and y
like if x and y are in sigma then x and y are elements ? or are they some powerset or subset of sigma?
if x and y are in sigma, they are sets of the form
{1,2,...n}
Also in discrete math I just dont understand the idea of writing a proof in general...
like I can explain it in words... but how do i make it into math expressions
yea but if the form is the same, doesnt that means that x and y are the same ? or is n different for both of them ?
so Sigma = { {1}, {1,2}, {1,2,3}, ... , {1,2,3,...,n}} ?
sigma = { {1}, {1,2}, {1,2,3}, ... }
it has infinite cardinality
i mean it doesn't have a final element
@limber heath Has your question been resolved?
so now I known this
and I understand that x and y are gonna be unique in the sense of the number of elements and what they are
and I also understand that if x and y are unique one will have more elements than the other
and as they have repeating elements, one has to be a subset of the other
BUT HOW DO I Write it as a proof
@twilit nacelle
x and y don't have to be unique
i'm not sure exactly what was covered in your class, but i would try to say something like this, for part (a):
$x = {1,2,\ldots m}$ and $y = {1,2,\ldots n}$ for some $m,n \in\mathbb{Z}^{+}$. Either $m>n$, $m=n$, or $m<n$. In the first case, for all $y'\in y$ we have $1\leq y'\leq n < m$ so $y'\in x$. This means that $y$🙁$x$.
Axe
and so on, for the other two cases (m=n and m<n)
oh okay
wait so proofs can be written like this??
we have been taught that it has to have some amount of propositions or some kind of infereicng or something to show. you cant just say stuff
could you give an example?
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Die Gleichung (\mid x-2\mid =5) besitzt mit (x \in \mathbb{R}) folgende Lösungsmenge (L:)
Subniif
this question is hard but what do these lines mean
Absolute value. Takes the positive output of any real number.
i.e., turns something like -3 into 3.
,w graph abs(x)
im insanely confused
|-3|=3.
but why
ahhhh
no
Yeah.
So, if |x| is defined as the distance of x from 0, wouldn't the output always be positive?
ye
Do you see why I said what I said earlier?
yes
so the answer of this should be 7
For the positive branch.
just 7 right
wait im a touch confused now
can you walk me through the question just so i can understand the thinkng behind it
Ok.
Try to understand this.
ok
so if x between those lines (im sorry idk how to put that w my keyboard lol) only has a positive answer then x stays unchanged
Yes.
and if x between those lines is negative then x inverts and becomes positive
oh i found the lines on my keyboard ||
Yep.
Yes
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I think it wants me to do it with vectors/linear algebra if possible (calculators allowed)
I solved it through equating magnitudes AB=AC=BC, then adding in another equation relating the angle ABC using dot product
But it took me a whole page. In the exam its only 2 marks and theres only 7 lines, so i'm asking for ideas on probably the most efficient method
Distance formula?
All sides of the triangle are the same length, you can get this length by calculating AB, then equate the distance BC and AC into this value.
There isn't any reason to add the third equation with the dot product, AC = AB and BC = AB are two independent equations.
When it wants me to verify, can I just substitute it in or do I have to show it by solving it myself?
idk how your teacher marks it but it should be sufficient to sub in
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yk slopes and stuff..?
(if yes use tan theta = |m2-m1/(1+m1m2)|)
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this is super open-ended, but is anyone here familiar with actuarial math/financial math/working with data?
@neat scarab Has your question been resolved?
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Hello, how do you solve for question 2c? Is my method correct? Because the Ans sheet said is ‘5’
So, when you do the brackets 1-4(x +5) you don’t get -3?
the multiplication takes priority over the subtraction
do u mean the wolf thing
bc i aint do no multiplying
just rearanging
i mean what op did in their work
ohh
Oh, so there isn’t -3(x+5)?
no
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every point on a plane can be written as linear combination of the other points on the plane? regardless of the position vector?
say i used b as my position vector
i can choose any linear combination of a,b,c in my direction vector?
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how this step change
multiply by $\frac{\sqrt{2}}{\sqrt{2}}$
ℝαμOmeganato5
at your level, its what's preferred
but as you get higher, noone really cares about roots of integers in denominators
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Find the area of inscribed circle in pi unit sq
hint:
(r×15/2) + (r ×14/2) + (r×13/2) = √21(8)(7)(6)
continue it
good job (it should be right)
how to close it?
write ".close"
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fyi with the method you can derive the formula for the inradius of the triangle, which would be r=A/s (A=area, s=semiperimiter)
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Hi I'm trying to understand what being a 'normal number' actually means --> from what I can gather it means that any digit in the decimal expansion in that particular base is equally likely to occur, but does that guarantee that some particular combination of digits is going to occur?
I'm a little confused by the wikipedia page
@slender tartan Has your question been resolved?
yes
any digit is called "rich"
any combination
or idk
wikipedia is very unsure what it means
@slender tartanit's probably the same thing
if a digit is random, independently of other digits, then inevitably every sequence is equally likely to occur
yeah, i'm confused too nevermind
me too 💀
@slender tartanit's certainly true though
ok, i misunderstood the question
yes, anything you could think of is guaranteed to occur
there's a high res jpeg of eiffel tower in a normal number
and that's weaker than normal
if you can find infinite amount of anything you want
that's only rich
wdym by rich
it's from wikipedia
normal number page, tells you about rich numbers, where anything occurs at least once
but that means it occurs at least any amount of times
i was initially trying to prove there are 2 consecutive zeroes in the base 10 decimal expansion of sqrt(3)
i don;t know how to prove it
but i just realised sqrt(3) hasn't been proved normal yet afaik
but thanks
this is kinda interesting
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Use maclaurin series for $f(x)=\frac{x}{\sqrt{4+x^2}}$
BrettASUS
$g(t)=(4+x^2)^{-1/2} <=> \ln{g(t)}=-1/2\ln{(4+x^2)}$ ?
what's exactly the question
you need to expand the function using the Maclaren series?
yes
ohk
BrettASUS
T&C
okayy sorry for the inconvenience
BrettASUS
yeah
id find the 1st few derivatives
you know the expansion formula no?
keep it as ^(3/2) PLS
yeahh
OOPS
BrettASUS
okay
ty ❤️
sheep in wolfs clothes
maclaurin series centers around c = 0
yup
so some derivatives will be 0
ohh yeah shit
BrettASUS
you are literally multiplying 0
with something nonzero
so $-\frac{1}{4^{3/2}}$ ?
BrettASUS
ong fr no cap
no.
$\left.\begin{aligned}\frac{-x}{(4+x^2)^\frac32}\x=0\end{aligned}\right}\implies\frac{0}{(4+0)^\frac32}$
so it is zero?
Bonk
yes
but I said that
g'(0)=0
so take out the 4
you'll get
$2\sqrt(1+\frac{x^2}{4})$
what is it with the sqrt(()
$\frac{1}{\sqrt{(4+x^2)} = \frac{1}{2} * \frac{1}{\sqrt{(1+\frac{x^2}{4}}}$
use \sqrt{}
not quite but you get it
T&C
BrettASUS
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
okay i give up
but i understand
I am lowkey hurting latex at this point latex on IC right now
okay what now?
$\frac{1}{\sqrt{(4+x^2)}} = \frac{1}{2} \cdot \frac{1}{\sqrt{(1+\frac{x^2}{4})}}$
expand ( 1+x²/4) ^(-1/2) with binomial expansion
what?
you can prob so some chain rule thingy, yeah
whats the question
check the pins
Use maclaurin series for $f(x)=\frac{x}{\sqrt{4+x^2}}$
BrettASUS
gothendrieck casually spawns
this ur alt account?
sus account
yes
what u tried?
the maclaurin is related to the binomial expansion of (1+x²)
if you can expand the denominator with binomial formula you'll get through 90 of the question
f(x) = x/2 *1/sqrt(1+u) ; u = x²/4 apply mcl to the u-expression
yess
bro
ye that is what T&C said
-1/2 is not an integer
ye go into that
no problem continue wit it
why does it have to be an integer?
cause you are not supposed to work with some gamma function
what do I do then ;-;
look up the binomial coefficient
I did you have two
one with k element R
and one with k >0
but one is for a finite series and one is infinite
u look up the generalized binomial coeff
yess
we got told to use the k element R one
so my answer is correct?
more like T&C's
idk didnt check, but follow what T&C said
u gotta expand that even more
$\binom{-\frac{1}{2}}{k} = (-1)^k \frac{(2k-1)!!}{2^k k!}$
for n=-1/2
i need to expand the (-1/2 n) i suppose?
alright and add the 1/2 to the sum
okay wait please imma try
T&C
how did you figure that out?
um the terms fall into a pattern
BrettASUS
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idk where the error is anyways
how can I like simplify the top part
(-1)(-3)(-5)?
i suppose that is the (-1)^n (2n-1)!!?
yup
now this n was inside the summation
put n=0,1 and so on
yupp doesn't matter
you just figured out the coefficients for the 1st 3 terms
now use these in the expansion of the summation
what do you mean?
here
simplify a lil bit more
4=2²
you mean with the 1/4 and 1/2?
yeah
alright
it'll be easier then to calculate the net coefficient
yess!
calculate for a few terms. how many terms do you need to expand up to??
i just had to give the maclaurin series of the function
so i think this is enough
ahh yeah then this form will be enough.
btw did you multiply with x? becus we were figuring things out of the denominator. so dont forget there was a x already in the numerator
the x from x/sqrt(4+x²)?
yeah
ye i did add that already
oh i made a mistake at the end
it should be 2n+1
idk why i did that there
yeahh whats wht I was thinking also check the power of the negative 1
oh yeah
alright thank you very much 🙂
okay!! it was a pleasure
make sure you verify the solution though 💜
how?
with your professor
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how should I try to solve this? its very vague
Row reduce it
try finding a theorem in your notes about when a unique solution exists
And get a compatibility eqn
sorry what do you mean?
gaussian elimination
Like this?
,rccw
,rotate
This precalculus video tutorial provides a basic introduction into the gaussian elimination - a process that involves elementary row operations with 3x3 matrices which allows you to solve a system of linear equations with 3 variables. You need to convert the system of equations into an augmented matrix and use matrix row operations to write it ...
watch this video
it explains everything
You would be able to solve these kinds of questions easily
thanks man!
Good luck
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Could someone explain what Im missing here? Im trying to understand the area of a circle formulas, but some things are weird
like, why does the circumference times the radius = twice the area? shouldnt it just = area? how do you get area(2) from that?
like, im getting a mental image of (radius)(circumference) just being the the radius taking a revolution around the center of the circle, giving you the area. if anything, id assume the diameter times the circumference would be area(2)
Think of the area of the circle as made up of concentric circles
okay, i can do that, yeah
Notice how the concentric circles slowly decrease in radius
okay
So consider each concentric circle as a strip of very small width h
What will be the area of that strip?
itd be the very small width times the length of the strip, right
its a circle so pi r 2, right
Not quite
It will depend on which concentric circle we are taking area of
The concentric circle closer to the centre will have the length equal to a smaller circle's circumference
If I'm reading this correctly, that only applies to a unit circle.
No? It applies to all circles.
yeah, because circumference is just perimeter of a circle
"why does the circumference times the radius = twice the area?"
Right, so when we are making up the area, we are adding up smaller and smaller strips yes?
There is a difference in how the two things are measured. One is a unit of length, R^1, while the latter is a unit of area, R^2.
yes, thats true
2pi r * (small width) + 2pi (r - small width) * (small width) and so on till 0
No? We are multiplying two length measures to get the area measure
"why does the circumference times the radius = twice the area?"
Read what OP asked.
So if we sum over all of them, what can we take as common factor?
That statement is true for all circles
2 pi?
And also the small width
So what do we have as a sum?
r + r-small width +.. so on till 0
2pi r * r = 2 pi r^2. Ok, now I'm on the same page.
i mean, its got to sum to the area, right
Since we are summing smaller and smaller radii
Going from r to 0
The avg is gonna be r/2
yeah, thats true
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okay
i think im starting to kind of see where youre leading although im still a little lost, ill watch this right now, yeah
thanks for the help both of you
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wait a second, i think i get something
like, i havent finished the video (showering to help me think) but i think i understand like, why radius * circumference is 2x area
if you took the circumference of a circle and then laid it out as a flat length, you could multiply it by the radius to get an area, yes
but youd end up with more area than expected, because a circle has less area than a square of the same height and width
a circle is made of cuts of triangles compared to a square which is cuts of squares, and since the area of a triangle is half of the area a square in the same dimentsions would have, the area youd get from radius * circumference is twice as much as is accurate
so the area of a circle would be the radius * circumference divided by 2
at least thats what im currently thinking, ill continue the video yeah
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instead of doing a case 3, can i just write WLOG on case 2?
yes
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I think that this is where i need to use l'hospital's but im also not sure
sick then lets try algebra first
just factor 2^n
6^n?
how
i was thinking 2*3=6
factored 2^n
ohh okay
we can rewrite it a bit better taking 4^n
u-sub 
at first glance it might look like inf/inf the left
making u think lhopital
but with one trick you can tell what it really results to
how do i know this trick?
1^n/2^n => 1/2^n?
yes
any idea now what it could be
is it 0?
can you justify why
im pretty sure its because 1/2^n is a number getting really large quickly that is dividing 1 which is basically approaching 0 and then you have the same case in the numerator of 0/15
the right goes to 3/15 but yea
it's basically 0 times a constant which is 0
2^n becomes very large quickly making 1/2^n become very small quickly
ya this is what i was trying to say but mine explanation was just super confusing
i dont know why all of these questions are so hard for me to understand when they also seem like simple concepts, like doing this question was so simple and im like ya i can totally do this now but then i look at the next problem and i have no idea what to do again! its so frustrating
i guess that's life
so philosophical
only way is to try and fail and try again
if you wanna learn
i just guided you maybe that's why it felt kind of easy
ya maybe
okay but for this one isnt it always going between 1 and -1 so wouldnt it be divergent?
but it said that was wrong
hmm okay isee your thinking
it oscillates that's what you are saying
but what happens with sin(14/n)
like yea it goes back and forth
but?
isnt sine bounded by -1 and 1 so it also doesnt approach anything
it approaches 0
yes
it becomes infact smaller and smaller
which means for sine
what does sine become for small values near 0
sine of 0 is 0
yes
sine becomes therefore also really small near 0 as n grows large
so yess it keep going back and forth
but the oscillation becomes smaller
it's like dancing around the x-axis
damn ya i see what you mean
the spinning cat is so random it makes me laugh every time
i can never tell what its supposed to mean
im dean rn
my trade mark
okay last math problem for today this one i also think that i need to do l'hospital's
just observe what's happening inside the ln
for large n
actually l'hopital is not quiet applicable
in my head all i see is inf/inf
like this?
Better thing to do before
the 7/n and 4/n go to 0
correct
yes
therefore..?
well then i have 3n/6n which is basically what i had before
n cancels
u already factored it why not cancel it lol
ohh oops okay then its just ln(1/2)
yes
if you even just need to tell the limit of some rational function then you can do it instantly with this trick
the 3rd applies to you since both numerator and denominator are linear
so you instantly can tell 3/6
nice to know
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Problem is to find the particular solution to the following differential equation using the inverse differential operator and noting the following.
I understand that i need to rewrite the particular solution in terms of this operator and the right hand side. y_p= L^{-1}(D)[tcost] then go from there but i dont really understand how im supposed to get some quadratic in terms of differntial operators out of this.
the bottom equation is when you have some L(D) =a_0+a_1D+a_2D^2
currently i have the following
Like i have a similar example from my prof but like it has a crazy jump that i don't really get and would like help with.
Like i know the next step is to do L(D+-i) = D(+-i)^2 +4 but i would like to understand why this works.
Never mind i got it just have an issue with the notation
.close
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Hello can someone help with regression analysis
!da2a
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Time series regression analysis
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.close
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how do i evaluate this
use series for cos
@lost urchin Has your question been resolved?
could also try multiplying and dividing by 1+cos(4x)
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Hello, can someone use rk4 to approximate y(0.2) , i just want to check my work im getting couple different answers
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@high raptor using an online calculator I arrived at about 1.24
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(note this agrees well with the actual value of the IVP, 4/(exp(4/5)+1))
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Problem 4: A woodworking factory uses mahogany to produce 5 tables per day. The cost for each raw material shipment is 5,800 USD, and the storage cost for one unit of raw material is 10 USD per day. Each table requires one unit of raw material.
The factory must order raw materials in batches, and the goal is to determine the optimal order quantity that minimizes the average daily cost, which includes both ordering costs and storage costs.
Question: How many units of raw material should the factory order each time?
5800/(5m) + 10m
m is supposed to be the amount of days in a cycle
m's value is 215,4
Therefore, raw materials's value is 215,4*5
Answer is 1077
Is there anything wrong with my solution
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Is the greedy choice property basically saying that there is only one local minima and that is therefore the global minima
How do I relate this idea of there being just one minima
To something like Dijkstras
If someone knows please confirm this
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I literally have no idea what this question is asking 💀
I understand everything before this part
This is the bit that I dont understand
Wtf is a
Sorry i see now too
And what line do they mean
1
the line passing thru the points at t=a and at t=pi-a
okay so use t=1 and t=pi-1
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Not at all 😭
okay so P_a and P_pi-a are just two points on the curve
the subscript gives a certain time
so for example P_1 would mean the point (x,y) that comes from t=1
you got me so far?
Yes I think so, but im still not really sure what to do
This question seems really hard
What do you mean instead of sry
They are still equal 1, no?
Oh wait nvm
I get you
I mean we can sub them in to x(t) and y(t) but im not sure how that would help us prove theyre in a vertical line
in math sometimes you just must try stuff
it sometimes makes sense if you are halfway through it
so i recommend doing exactly what u just said
and it will probably make sense when ur done
okay so P_a (cos(a)sin(2a),cos(a))
x(pi - a) = cos(pi - a)sin(2pi - 2a) = -cos(a)sin(-2a)
Is that correct? I tried to use identities
y(pi - a) = cos(pi - a) = -cos(a)
try again
