#help-27
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i applied quotient rule and got $(x^2 + a^2)^{\frac{3}{2}} - x(x^2 + a^2)^{\frac{1}{2}} * \frac{3}{2} = 0$
oh shit i found the mistake
i didnt apply chain rule
$\frac{u'v=uv'}{v^2}$
ren
yea exactl
therealtdp
no
where am i wrong
?
what happens?
i dont see a problem?
i think the denominator is $(x^2 + a^2)^3$
therealtdp
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Does anyone know how to do (1/2)^-2
what property about negative exponents do you know about?
Must have skipped a lesson or two
This must be what happens when you dive into pre calc
While not taking any math for 2 years
It equals 4 I have no clue how they got there
I kind of just assumed it would be 2/5 x 2/5
that would be right, but we want to use exponent properties
So exponents distribute to fractions, that is (2/5)^2 = (2^2)/(5^2)
= 4/25
Ok, and do negatives just follow a whole different rule?
sort of, you can still apply this though
(1/2)^-2 = (1^-2)/(2^-2)
now you need to know another property about exponents, which is that
a^(-n) = 1/(a^n)
Hm
actually, you can omit the step about disturbing the exponent altogether
by just applying this from the getgo
in your case, the “a” is 1/2 and the “n” is 2
Ah ok
so the rule tells us that (1/2)^(-2) should equal 1/[(1/2)^n]
which you can simplify I presume
Ok so it ends up at 2 and we then we raise it to the power of 2 again to get 4?
yes, that seems right
Ok good thank!
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Can someone check my work for part B and C
And help me with part A and D?
I have absolutely no idea how to do it
@rain otter can u send the full question please?
@rain otter Has your question been resolved?
this is the full question
@zenith summit
alright
okl its cos u said u wanted someone to check part b and c
ill take a look at a and d now then
Alright, thanks so much
its going to be a bit confusing to explain
okay
so part a
on your graph i want you to draw the line y=-1
and then picture what the volume of revolution would look like if its rotated around y=-1
(dw im not gonna leave it as vague as this but i want to challenge you a bit)
@rain otter should i tell you or can u picture it
yeah I drew that
so if you was to rotate your R around that line
its the same as doing a volume of revolution around the x-axis
but you have to account
for the cylinder
that will also be made
right
To find the volume, integrate e^y - (-1) - (0 - (-1) until the intersection point
and then integrate (5-y - (-1)) - (0 -(-1))
and integrate taht
add both
multiply by Pi
its your answer to part c + the volume of the cylinder that is formed
how do I find the volume of the cylinder formed?
you know the radius
and the length
(the length is from your 2 x intercepts)
then apply the volume of a cylinder eqn
pi * r^2 * l
so 1 = r and x-int = 1 and 5?
yeah so your l would be 4
But don't I use the shell method to integrate it?
you would get the same answer
wait
no
so pi * 1 * 4
its alr
try integrate it via the vol of revolution method
you would still get 4pi
integral from 1 to 5 of 1 with respect to x
all multiplied by pi
would be 4pi
so i wasnt bugging
and add that to ur part c answer (assuming u was correct for part c)
ok, but my answer to part c is 112.030
the total for Part A + B + C + D is 130.055, which is given in the stem
so if I were to add 4pi to 112.030, it would exceed the total
which means I'm wrong with part C
i guess
right
or the answer to part d is very small
And since the upper curve of integration changes, I would need to split the integral for part C
4pi +112.03 is less than 130.055
maybe
that makes my part C correct
Wait do u mind checking my Part C just in case?
Im so sorryy
im a bit rusty but ill take a look rq
thanks so so much
u did square ln x and (5-x) right
no because I'm just taking the area
I did square the total of the antiderivative of ln(x) and (5-x)
and multiplied it by pi
volume of revolution around x axis is pi * the integral of y^2 though
i dont know if this will get you the same thing
ill check rq
ill check but i doubt it tbh
okay
Most beautiful handwritten integral signs I have ever seen haha
ok
i did it the other way and ended up with 8.746 which is equally sus
I have to square it
wtf type of questions are they giving you guys holy
@uncut hornet bro check this question
unless im being braindead
Ikkkk and I have a test over all this today
I got 97.397
trust your answer not mine
honestly good luck
i gtg now
sorry i couldnt be of more help
i cba helping w volumes of revolution
thats alr, thanks so much for ur help, truly
@rain otter .closed or .solved when ur done btw
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How to solve this problem without the graph?
@solemn sinew Has your question been resolved?
@solemn sinew Has your question been resolved?
@solemn sinew Has your question been resolved?
@solemn sinew Has your question been resolved?
(don't mind me, I'm still working on it)
sin(2pi/3)
= Im(e^(2ipi/3))
= Im(e^(2ipi * 1/3))
= Im((e^2ipi) ^ 1/3)
= Im((-1) ^ 1/3)
= -Im(1 ^ 1/3)
we want the negative imaginary component of the 1st 3rd root of unity
(where 0th = 1)
we know they're spaced evenly
=> form an equilateral triangle
oh wait you could also do it over the taylor series
anyway, this is the 30-60-90 triangle
guess what: two of these make an equilateral triangle
therefore, the short side is 1/2 the hypothnuse
the other is therefore sqrt(1² - 0.5²) = sqrt(0.75) = sqrt(3/4) = sqrt(3) / 2 the hypotenuse
the hypothenuse is one
the shorter side therefore 1/2
the longer, the one we want, sqrt(3) / 2
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How would you go about factoring a question that is x^8 + x^4 + a constant in the same manner that you would factor a question such as x^4 + 9x^2 + 20 being (x^2 + 4) (x^2 + 5)
set x^4 = y
the polynomial can then be written as y^2 + y + a, which you can use the quadratic formula for
What about the x^8
Can you make an example if possible?
start with x^8 + 2x^4 + 1 = 0
set y = x^4 -> y^2 = (x^4)^2 = x^8, so x^8 = y^2
then we can substitute into the equation
y^2 + 2y + 1 = 0
solve using the quadratic formula to get
(y+1)(y+1) = 0
sub back in
(x^4 + 1)(x^4 + 1) = 0
Thank you
How would you go about using completing the square to factor a polynomial that starts off with a degree of 3 or more
do you have an example in mind
No I do not, my teacher just said it would be on the test but we do not have any examples
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How to solve this question?
In the given figure, ABCD is a square and BHGF is a rectangle. If BE = BH, prove that the square ABCD and the rectangle BHGF are equal in area.
The figure is in the image
what have you tried
@shut oak Has your question been resolved?
1)Area of triangle ABE=1/2 AREA OF SQUARE ABCD[STANDING ON SAME BASE AND BETWEEN SAME PARALLEL LINES]
2)AREA OF TRIANGLE ABE=1/2AREA OF RECTANGLE BHGF[SAME AS ABOVE AS BH=BE]
3)AREA OF SQUARE ABCD=AREA OF RECTANGLE BHGF[FROM (1)&(2)]
I tried this
is this correct?
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does anyone have an idea on how to understand which one of these two functions goes to +infinity faster as n->+infinity?
id need to understand which one is bigger between 11/2 and log(4/3,3) but i have no idea on how to do that without a calculator
oh that's 4/3
i can tell you the right one goes to infinity faster for large n, but over that interval im not sure
looks like n/3
me too
it's probably n/3
nope its actually 4/3 i dont have the best handwriting 
you can bound log_(4/3)(4)
don’t need to get a good approximation
for example, is it less than 10?
the fact is that i need it to calculate the complexity of a function and i need to know exactly which one is bigger and by what margin but it seems impossible without a calculator
no it’s possible without a calculator
i claim log_(4/3)(4) < 10
can you see why?
we need something a little different for the problem but it’s just an example
log_(4/3)(4) < 10 is true because 4 < (4/3)^10
yea that makes sense
knowing log_(4/3)(4) < 5 would solve the problem right?
yea it does
thats exactly what i was doing rn after you said this
it makes a lot of sense, thank you :D idk why i didnt think of that

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Help😅
I need formule for volume and surface
Pls 🙏
Someone
I just need to know how to get the length of a line underneath 45°
Do I use sin,cos,tg,ctg or something else
this question isn't very clear but it definitely will require trig; rephrase since i can't really understand wdym
I need to get formula for the length of the line under the 45°
When I know that I can use PT to get everything else
@manic tundra Has your question been resolved?
No
@manic tundra Has your question been resolved?
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Is this correct
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the question was to calculate the five number summary for the set of data in the image. i was wondering if somebody could check my working and let me know if i did all my calculations correctly or if i made any mistakes.
i’m aware that this is simple maths but i really need to double check with somebody
@ocean socket Has your question been resolved?
<@&286206848099549185>
<@&286206848099549185>
@ocean socket Has your question been resolved?
<@&286206848099549185>
Yep, it checks out. Ur right!
thank you sm i appreciate it
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Determine the matrix X such that it solves the matrix equation
Since A does not have an inverse thus i can't move it over to the RHS to solve for X. How do i go about solving this?
what size would X need to have
2x3
ok
lets say the first column of X has entries (x1, x2)
what can you say about those
I'm not sure sadly
I don't understand the question?
what is A*(x1,x2)
= x1 + x2 ?
what happened to the rest of A
you seem to be assuming that x1 = x2, and similarly for the y's and z's
Also this would be the first row that you would get
I'm mainly interested in the steps to solve it
Normally i'd take the inverse and solve for X but that isn't possible
There’s the second and third one too, which is what was asked for 
$x_1+x_2 \
2x_1+3x_2 \
x_1+2x_2$
Merineth
Like so?
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I'm given 3 vectors v1,v2,v3
and i'm supposed to find all vectors that are perpendicular to v1 v2 and v3
why on the final step of gaussian elimination
Does the answer become t(4,-1,3,-.1) ?
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Let a be a non-zero complex number such that |a| $\neq$ 1. Let P be the point a in the complex plane, and let Q be the point $\frac{1}{\bar a}$. Let $C_1$ be the circle ${z : |z| = 1$} and let $C_2$ be any circle passing through P and Q. Show that $C_1$ and $C_2$ intersect orhtogonally. [Two circles are said to intersect orthogonally if the tangents at a point of intersection are perpendicular to each other.]
Normed
I've made the diagram but not able to show that the circles intersect orthogonally, can someone help?
@livid carbon Has your question been resolved?
won't be available in a sec, but the procedure is:
determine a general circle formula for all circles that pass through a and 1/a-
then determine the intersections of the given unit circle and that variable circle
at these two intersection points, you can show orthogonality via the direction vector
or normal vector
either would work
the normal vectors of a circle are directly pointing outwards, so since you have it in radius form
that makes it more straightforward
than e.g. x=sqrt(1-y²)+2
if you're unsure how to get the circle formula you can also look up how to construct a circle from two given points
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i've thought about simply arranging the pears in consecutive order
ie boxes of 0+1+...+10
however this is 55
not sure where to go from here
so, this shows that 11 boxes would be necessary this way and 12 isn't possible when packing the pears. But 11 doesn't divide 60 so the apples wouldn't be evenly distributed. So what is the other maximal option?
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Heyy, how do I make the function f(x) = ax^2+bx+c and f(x) = a(x-x1)(x-x2) into this function? a(x-m)^2+n?
Is it even possible
vague question.
how so?
x^2-4x+3 for the ax^2+bx+c
and for a(x-x1)(x-x2) = -(x+2)(x-3)
Now how do I turn these both into a(x-m)^2+n?
By Completing the square
😭 could I please get a formula of how
Cause i've been trying to do that for like 40 minutes
It does not have a formula, it has multiple steps which you can find on YT
You can also try searching for converting quadratic equation to vertex form
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The W point is the center of the PQRS square, and the U point is the center of the RS side. The segments TW , UW and VW divide this square into three equal parts (in terms of square area). What is the length of the segment SV if the side of this square is 1?
The answer is 5/6 but I don't understand really why
<@&286206848099549185> if something isnt clear let me know
@onyx pivot Has your question been resolved?
<@&286206848099549185> i think i need to find a way to calculate the area of PQVT in order to calculate VSUW area but i dont know how to calculate the PQTV area by using some formulas or anything, like im completely blank in terms of it i only know that the distance PQ is 1 and the height is 1/2 but im missing something i guess, i know that only PQTVW = VSUW = WURT = 1/3
its not a test btw
if anyone is wondering
its 2 years old and from a competition
Hi
hi
Ok so, we'll need to express the areas in terms of the sides
okay
We want SV, so let's call it x. This means PV is 1-x, we are assuming that we have symmetry about WU, which doesn't seem to be actually stated
We know that WU is 1/2
So the area of the pentagon PVWTQ is the area of triangle VWT and the rectangle PVTQ
Extend WU into the line VT and it intersects at a right angle, let's call this point A. WA = 1/2 - (1-x) = x - 1/2
So the area of the triangle is 1/2 WA * VT = 1/2 * (x - 1/2) * 1
Or x/2 - 1/4
The area of the rectangle is 1 * (1-x) = 1-x
So we get 3/4 - x/2 for the area of the pentagon
This is equal to the area of the trapezoid WUSV
This will give you one equation in x
i see i see
Then you just solve
thanks
Yw
Have to help my fellow pokepfps
ofc i need to get smart someday
Can you translate the full question?
You already speak one language more than I do.
In every of these two identical isosceles triangles with a right angle, inscribed a square like shown on a picture. If the square P has 45cm^2 area, then the R area is?
Oic
Ok, so you have a lot of similar triangles here
We have in particular that by symmetry, P goes halfway to the edge
So the total area of the triangle is twice that of P
Next, for R the three smaller triangles all have hypotenuses that add up to the overall hypotenus
Sorry, my bad,
The smaller triangle hypotenus+ 2 longer triangle edge
uhhh
Let's say the side length of the big triangle is x, and the medium y, and the small z. so we have x√2 = 2y + z√2 and x = z + y√2
Which upon reflection is the same equation twice, hmmm
Oh we also have z √2 = y from the sides of R
So x√2 = 3y
i dont get it
okay
R diagram:
Top left A
Bottom left B
Bottom right C
R square starting from top and going clockwise: QRST
We know that RS = ST, so BS √2 = CS
And we know that AC = AQ + QR + RC
So AQ = AB/3 * √2
We know that 1/2 AB^2 = 90 from the previous so AB = √180 = 12√5, I believe.
seems somehow logical
So AQ = AB/3 * √2 = 4√10
wait
isnt sqrt180 6sqrt5?
sure
QR = 2√10 then
So QR^2 = 40
I'm going to crawl back into bed for a little while and drink some more tea
Remember that QR is the side of the square
I wrote AQ before, which is equal to QR, because I got them mixed up.
This is just the line segment AC broken up into 3 shorter segments joined end to end
One sec
ohhhhhhh
wait a sec then
why do we know that RS = ST and then BSsqrt2 = CS? @faint zinc
like rs = st i understand
but the 2nd part not really
Because of the triangles around it
Triangle BST and triangle RCS are similar and have a relative scaling factor of √2
why RC
Isoceles right triangle RCS
so thats just how it works?
that AQ = QR = RC?
i dont understand
thats where im stuck at
in my drawing
@faint zinc
Sorry, zonked out currently. AQ = QT (triangle AQT) and QT = QR (square)
That's why AQ = QR = RC
All of the triangles are 45-45-90
Which is why any of this works
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Randomly choose 3 vertices from a regular dodecahedron. Calculate the probability of picking 3 vertices of a non-isosceles right triangle
i dont know where to start
this is my sketch of a dodecahedron
what i do know that for the vertices to not be isosceles, the 3 chosen points must not be adjacent
but what about the condition for them to create a right triangle?
hmm that seems hard to count all the cases of
from the picture it looks like these are on top of eachother and would make a rectangle to give right triangles
so u want to simplify the problem
a regular dodecahedron has very nice symmetry so the first thing u should do is to fix a single point, then your problem is is to randomly pick 2 other points and find the prob. these 3 points outline a non-isosceles right triangle
(strictly speaking, this is optional. but it's useful as i alrd see u made a counting error in the number u posted above)
the opposite sides make a rectangle
and there are 4 ways of picking 3 vertices from it
and since there are 10 rectangles in our dodecahedron
so, 40/1140?
again no
that's why i'm suggesting the simplification approach above
but if u really want to do it ur way, then carefully count how many edges a dodecahedron has
hmmm
wouldnt the prob be different for each sides?
take a close look at the diagram u have
doesn't it look kind of the same no matter what vertex u view it from
oh yeah i suppose so
indeed a "regular dodecahedron" is one of the platonic solids so its properties r very nice
so lets say i pick a fixed point
now could you hint me of how to find the prob of picking 2 other vertices that create a right triangle?
here's the points that are symmetric compared to the red fixed points
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could someone explain the logic to me on this one?
its a circit and the probobility for the device to work in on the rectangle
@gentle mantle Has your question been resolved?
each of the 3 segments (left, middle, right) must work for the entire device to work
for a segment to work, at least 1 of its 2 components must work
so, for a single segment (let's say the left-most one)
P(the segment works) = P(at least 1 component works) = 1 - P(both components fail) = 1 - (1 - 0.9)(1 - 0.95) = (1 - (0.1)(0.05))
and u repeat this thinking across the entire circuit
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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 was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
lost
https://youtu.be/VkRYjSa3BlM?si=Jxn4GNSVPFBXJ-hJ check this video out
In the game of Tetris, there are 7 pieces, each made up of 4 square units. (The shapes are called "tetrominoes" in mathematical literature.) Here's the puzzle. Can you use one of each piece to form a 7x4 rectangle? If so, find a way. If not, prove why it's impossible. Thanks to Doctor Perkins for sending me this problem!
My blog post for this v...
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do you know the definition of n choose k?
yeah n!/(n-k)!k!
plug in k=3, and see what you get
notice that n! = n * (n-1) * ... * 1
and (n-3)! = (n-3) * (n-4) * ... * 1
meaning n!/(n-3)! = n * (n-1) * (n-2)
how does plugging in 3 show its even though
is this part clear
oh yeah cause (n-3)! cancels
try it first, youll get (n)(n-1)(n-2)/6, and since n is even just say n=2m
since 3! = 3 * 2 * 1 = 3 * 2
try to see where to go here
and now you can directly show that it's even
yeah directly refactoring, inserting n=2m or using induction all prove it 🦇
so plug in n as even number and solve it would result in a even expression
yea but you could also directly see it here
since from among the terms n, n-1 and n-2
one of them is divisible by 3
and two are divisble by 2
thereby the total product is still even
since at least one factor 2 remains
how do you know its divisiblity
because they are three consecutive numbers
which means one of them is multiple of 3
since if you look at all natural numbers
you see that each third number is divisible by 3
oh, you could imagine as even×odd×even/even which is still even
yop
oh that makes sense
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Can you send the graph too?
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I already solved the differential equation but I wanna ask what do I have to do with the extra small questions in the question itself
I checked the answers and I got it correct
But the answer doesn't show how it came to be, thus skipping out the questions that has to be [shown]
Pinging helpers every 15 mins
@bronze willow Has your question been resolved?
<@&286206848099549185>
@bronze willow Has your question been resolved?
<@&286206848099549185>
@bronze willow Has your question been resolved?
<@&286206848099549185>
<@&286206848099549185>
<@&286206848099549185>
<@&286206848099549185> All of you are genuinely so slow that I have another question I have to ask here
!vol
Helpers are just people volunteering their time to help you. Be polite and patient.
@SandAnth what is your problem?
-Is my method of solving the differential equation correct, that's it
@sandanth What is your problem?
I'm sorry I have to be that way, I've been waiting for 2 hours
Do not forget this
Question 11 and question 14
Hold on, I am reading the question
Most people in this discord are full time students and dont have much free time to spare 😭 Everyone does get answered eventually though
2 hours man
Wait til you find out it takes months to get answered on math stack exchange
Must be complicated I bet
I cannot solve question number 14 as I don't know calculus. But ques 11 seems to be under my jurisdiction. @sandanth
Have you thought of anything up until now?
Is this working to do w the first part of the question?
Is that what youre struggling with?
wait its all one question
mb
misread
I guess I'd consider the 1st part to be finding the general equation
2nd part is basically extra questions surrounding the general equation
But I cannot process the function of the components itself
Yeah so youve found the equation n it looks right
Confirmed it with the answer in the book yes
Note that the answers do not show the steps of each questions
If it did I would not have been here in the first place
Do you need help with the next parts then?
Yes I do
Showing that it reaxhes those values under those conditions
so for the first one, consider what happens when t -> infinity
or just any large number
As that will represent the process repeated many times
1-e^(-kt/A) tends to 1 right?
yss the half volume bit
Which variable is considered the volume?
I think x refers to the depth at any given point, so the time taken for that value to half is x/2 yes
How would you show that k is that value then?
Okay so basically we’ve established that w/k is the value after a long time t
We can consider that the maximum value of x
Omg I have not taken that into consideration
If x has to be half w/k has to be multiplied by 1/2 is it?
yes
so you will get
w/2k = w/k(1 -e^kt/A)
where you can just start off by cancelling out w/k
giving you 1/2 = 1-e^-kt/A
then from there basic rearranging then ln
congratss
Still have this one tho
yep looks right
I dont even know where to begin with this one
I wish there were answer steps to this because I literally cannot comprehend how to form equations off this
<@&286206848099549185>
Pinging every 15 mins from noe
God I hate word questions like this
rate of change in concentration
your concentration is initially 1kg/100litres
or 10g/litre
As a function of time
your concentration would be 10,000/1000+5t where t is number of minutes
Questions needed help on: 14 and 15 (these are definitely the only ones I need help on)
Question 14:
Am I doing this correct?
If else, state what I am doing wrong
Question 15:
What should I do first in order to form the differential equation?
Answers are given, but not the steps tp it (I hate this book for that)
^ As t increases, your total volume of water increases and conc. decreases
wait
Dont forget that that water flows out the same rate
That's what stumping me in the first place
dv/dt = 5 ltr min^-1
Thats it?
one sec
water flows out
uhh
You would have to assume that the mixture loses sodium hydroxide
constantly then
This is about the table salt and not the water right?
Yes as the actual volume of water wont be changing
Youll just lose sodium hydroxide
And how much you lose is to do with the concentration
To begin with you have 10g/litre
And if you lose 5l of water in a minute, you would lose 50g in the first minute
Its gonna be an inversely proportional relationship
take concentration as a function of time
dc/dt being proportional to 1/m where m is mass of sodium hydroxide
wait
no
my mind fried
the final equation should follow something like c = c0 e^-At
c0 being initial concentration
A being some constant i cant think of rn
Hol on
Before the general solution
Whats the differential equation you came up with?
I cant think of one rn, my minds exhausted 😭
I just know how the shape of the graphs gonna look
dm/dt = dc/dt * v i think
so dm/dtv = dc/dt i think
not certain
Might have to ask around some more
For the differential equation
Since water is added to the saltwater at a rate of 5 litres min^(-1), then the amount of salt is going to be diluted at the same time at a rate of 50 grams min^(-1)
And if the saltwater solution is also going down at the same rate, the amount of salt going out of the tank is gonna be another 50 grams min^(-1)
Both of these are going through the same time, t
So -100t
Or -0.1t in kg
I just tried it and i got 0.2278 which is short by quite a bit 😭
Probably a unit error
i took dc/dt = -5c
wait thats only the mass
try dc/dt = -5c/1000
might be different
Yeah that gives the answer
over complicating it for what 😭😭
my apologies
The dilution of the mixture is to do with the removal of sodium hydroxide
Not the addition of water
The addition of water is just to counteract the loss of water
To keep the volume constant
The waters going to be a constant volume of 1000 litres
And the loss of sodium hydroxide per minute is 5c
So the decrease in concentration at any given momement in time is -5c/1000
change in mass/volume
change in concentration
Ywah im sorry for overcomplicating it to begin with 😭
gove me a second
@bronze willow Has your question been resolved?
Hello
only 1 question left
<@&286206848099549185>
whatever
I had help and I thought the answer was weird, but ngl it seems legit so I'm just gonna count it as an error in the book
anyways, thank you to everyone who helped me
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this might be a dumb question but i dont know how to solve this
Here you can use the cosine relations (sorry if it's called something else, not native language, don't know the english terms).
wait all i have to use is cosine rule?
Seems that way, yeah.
ok thanks

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@restive river might also have to use the sine relations as well.

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I have tried looking up how to do this one million times and I have answered one of these questions right only because i guessed and somehow got it right but this website has never gave me trouble until now becuase it never taught me how to find the p value it just always says "use technology" 🤬 does anyone know how???
@quasi mountain Has your question been resolved?
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Hi Math help!
I’m working on a set of homogenous and 3 variable system of equations
The question is #36
The final solution was 0,0,0
But I don’t get what I essentially did that was wrong?
do you still need me to help
Also when dealing with three variable system of equations. Idk when the let z = c. Do we always eliminate x first?
I get diff answers depending on the first variable I eliminate
@grave acorn Has your question been resolved?
Why do you think that's incorrect?
You shouldn't
Like for example
If I set z to c
My solution will be different from someone
Who sets x to c
And idk if mine is incorrect as a result
Indeed, that would make one of those solutions incorrect
No matter the method, the solution should be the same
The solution in purple is what my prof gor and the one underneath it is the textbook answe
But according to the prof both r right
She did a diff procedure
Idk what I did that was incorrect
Gotcha, there's a family of solutions.
If both works are correct, then this is actually the same family, but different descriptions of it
,w matrix row reduce {{5,2,3,0},{3,1,-2,0},{4,-7,5,0}}
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this is a non calculator question on a timed test
is there even a fast way to do this
i feel like the question was also vague
We can’t help with tests. It’s against the rules of the server
its a practice test
this is a revision
to see what i have done wrong
and practice for the real one
It's MCQ so the fast way is to not add exactly, just estimate to the nearest 50, 418 is wrong because that is the 'rest' that is evenly distributed, not the amount at S Paulo hospital specifically
nearest 100 would probably do if mental maths is not your strong suit
its like
i took too long to interpret the question
and jsut kind of guessed
ill try again
Yeah Qs like this are kinda horrendous, a lot of aptitude tests many moons ago when I was applying to airlines had Qs like this, the more you do the easier it gets
In the early stages, write the key numbers on a notepad as you go to help keep track
That way if you get lost you dont have to start from the beginning
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I'm trying to write this with polar coordinates
you may want to double check the bounds on theta
I thought that might be wrong but I'm looking at the graph and the angle does go from 0 to pi/4
only if you're strictly in the first quadrant
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Why?
What log properties do you know?
I would go 1-by-1 on the options
simplifying
to see if they're actually equal or not
Show your work
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Have any clearer calculation method?
do you want the limit of the top limit
yes
well, let's try to bound it between two other limits
so what is the absolute minimum that cos x can be
0?
I closed your other channel. Stick to 1 channel only
cos x
you drew a graph of cos x over there
look
whats the minimum
try to form
smth <= x+cosx / x <= smth
using facts abt cos
btw is the 2nd image the solution?
YES
this is a specific case of a generalized limit method when there's a rational function and there's a cosine or sine there somewhere and it's going to infinity
anyways
whats the absolute lowest value of cosine
you drew a cosine graph
the cos x/x limit can be ascertained via squeeze theorem
-1
correct
and 1 is highest
so those are strictly less than or equal to cos x for the first one, and >= cos x for the second one
so we can rewrite the original limit
-1 <= cos x <= 1
-1/x <= cosx / x <= 1/x
lim x to infty -1/x <= lim x to infty cosx / x <= lim x to infty 1/x
0 <= lim x to infty cosx / x <= 0
you can separate the function as x/x + cosx / x
yeah but that cant always be done with limits of this form
oh wait they already did that in the board
we wanna learn the general lesson of "sin and cos are negligible at infinity in a rational function with x's on the top or bottom
so we can restate the equation as (x-1)/x<=(x+cosx)/x<=(x+1)/x
and these are both trivial
so we can apply squeeze theorem
alright
so what is lim x->inf of (x-1)/x
and then (x+1)/x
it's 1 right?
yep
now (x-1)/x<=(x+cosx)/x<=(x+1)/x
becomes 1<=(x+cosx)/x<=1?
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Does anyone know how to solve this, a guy needs it done
this too
this channel is occupied my guy
Are you guys taking a test together?
no @restive river did
💀
both questions are my math phomeowkr
lmao
Why did a different account open and post the question for you
bruh
so there are 6 rectangles in this shape
yes
and you want each rectangle to be painted only partially
upto 10 inches
ans the length is given as 27
so find the area of paint for one rectangle
and multiply it by 6
so what is your question
