#help-33
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the hint on the hw says to consider how many 1 digit, 2 digit, 3 digit and 4 digit numbers are possible
to a sequence of 5 digits
the main thing though i dont really understand the only 1-5 thing
that's not the best approach since we allow repetition
and the repetition is allowed makes it even more weird for me
well you have an arbitrary 5 digit number that's odd, less than 3000 and only uses the digits 0 to 5
your first digit has 3 options (0,1,2)
yes
your second digit has 6 options
second digit is in the hundreds?
im starting to understand
but where did you get the options for the second, third, and fourth digist?
oh right
so second digit has 6 options
likewise for third
likewise for fourth, except it's odd
so 3
oh and fourth has to be odd because an odd number is defined by its last digit?
ys
ok tysm
if you want to test your understanding attempt the same but without repetition.
i understand it now, was a lot more confusing when i first saw it but now im realizing how it works out
im unsure how repetition would change anything
since each number is different anyways
say we use 1 for the first digit
ok
that means we can't use 1 for the other digits anymore
meaning for the others we now strictly have ≤5 options
oh
so 3 * 5* 4* 2?
and the tricky part comes when considering that the last digit must be odd
yeah
nop
because you have different cases
say we took 2 odd and 1 even digits for the first three digits
now you only have 1 option left for the fourth digit
but if instead we only took even digits for the first three digits, then you have 3 options left for the fourth digit
how would we know whether the fourth digit would have 3 options or only one?
depending on which digits we took for the first three
of course we don't want to determine every single possible number that can be formed
so we split into cases
i thought there had to be a conclusive answer
there is, it's just a bit more nested due to the cases
ok
shall we briefly go it through?
ok
let's split it into these 4 cases:
For the cases I'll denote them with a number indicating how many odd numbers we choose for the first three digits:
[0]
[1]
[2]
[3]
meaning we can either choose 0, 1, 2 or 3 odd numbers for the first three digits
odd number = ends with 1 3 5 7 or 9
less than 3000
using digits 0 1 2 3 4 5
how many numbers can you make with 0 1 2 3 4 5, which end in 1 3 or 5
But it's already solved
Notice that if we took three odd numbers for the first three digits
i dont think my teacher taught us that
eg. "135?"
yeah
doesn't need to be taught, it's about the principle to make you more familiar with how to calculate the total number of possibilities
ok
Different tasks require different solutions
Then we can't choose a number for the fourth
because the fourth has to be odd
and 1,3,5 are already used up
meaning for the case [3] we have 0 options
now let's regard case [0]
so we only take even numbers for the first three digits
first digit has 2 options (0,2)
second digit has 2 options left from among (0,2,4) and third digit has 1 option left
and the fourth digit has 3 options: (1,3,5)
meaning in total we have 2*2*1*3 = 12 options
[0] = 12
[3] = 0
ok
ok now onto [1]
now comes the slightly more difficult part
since we now want one of the first three digits to be odd
we have from among three places to choose
if the first digit is odd, then there are 1*3*2*2 = 12 options
if the second digit is odd, then there are 2*3*2*2 = 24 options
if the third digit is odd, then there are 2*2*3*2 = 24 options
it's fine if you don't get to these products that quickly, but it's just going through how many options we have for each digit
alr
meaning our total for that case is: [1] = 12+24+24 = 60
three cases solved, one to go: [2]
now we have two odd and one even number among the first three
so we can regard it as "placing" a single even number among the first three digits
if the first digit is even then there are 2*3*2*1 = 12 options
If the second digit is even there are 1*3*2*1 = 6 options
and if the third digit is even there are 6 options too
[2] = 12+6+6 = 24
total options = [0]+[1]+[2]+[3] = 12+60+24+0 = 96
this would be the case-Splitting approach
as you see a lot more steps required
yeah
just for no repetitions
but there are concepts which simplify the above calculations
all of my homework which has that sort of idea in the problems all have with repetition
you might have also noticed that many numbers repeat, which can be summarized
Now you know why :]
It's mainly because your requirements like "the last digit is odd" become more convoluted
since now the number of options depends on what you picked for the other spots
nywys gl with the topic 🐛
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can someone please help me understand where it says y(0)=-1 what am i supposed to do
Like I don't understand what is going on there
am i supposed to plug 0 in for y and x
because it says C=0
if i plug 0 in for both that wouldn't get me C=0
so I am so lost
You plug in x=0 and y=-1
Every y on the left side of that equality (post-integral) is still a function of x, y(x) if you prefer
also quick question this work is wrong right it should be 3y+y^2 or am i tripping
so like C should actually be -2
because I think he did the integral wrong
yeah
I had a friend write these problems so they probably rushed the solutions out to me
its ok
just making sure I am not dumb and making a mistake
Oh it's not the instructor, alright that's not so bad
yeah yeah
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Hi
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Can I have help with 1.9
So far I have
I'm just not sure how to generalize for n. I have up to n=2 is correct. It's just after that
Maybe you should try posting in #linear-algebra or one of the advanced channels (idk where that would fit)
Not sure what that Lambda^p notation means
It's antisymmetric p type tensors
Ah yeah I prolly saw that notation once, not very familiar with tensors tho
What book do all these questions come from ?
There from an introduction to differential manifolds
Yeah you prolly should try the diff geo channel then
That makes sense
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can someone help me with this inner fellowship tangent and
tangent to external alliances, so basically i started with
6² = d² - (R+3)²
36 = d² - (R² + 6R + 9)
36 = d² - R² - 6R - 9
45 = d² - R² - 6R
then im finding the tangent to external alliances,
(4√6)² = d² - (R - 3)²
96 = d² - (R² -6R + 9)
96 = d² - R² + 6R - 9
105 = d² - R² + 6 R
and now im confused what should i next cause im stuck there
GSPD is inner fellowship and GSPL is tangent to external
<@&286206848099549185>
i cant find the r and d?
bruv
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i need help in further solving this aplication of laplace transform :
This is what I have done so far
@rigid mountain Has your question been resolved?
<@&286206848099549185>
help
help me
Laplace transforms, a complex scheme,
Help me decipher, this mathematical dream.
With your expertise, guide me through,
To unravel solutions, tried and true. <@&286206848099549185>
Chat got
You have the Laplace transform of the solution to the ODE, to get y you just need to perform the inverse laplace transform
To start write $$\frac{2}{s^{4} - 4s^{2}}$$ as a partial fraction
TomB
Apologies! $$\frac{2}{s^{4} + 4s^{2}}$$
TomB
my final part was L{y}= 2/s^4 + 4s^2 ...... so now i have to do inverse laplace transform?
Indeed, once you do the Inverse Laplace transform, you will have the solution to the ODE
ohhhhhhh ok thanks man
Happy to help!
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@mighty seal do i have to do it on both the sides ?
Indeed, but $L^{-1}[ L [y] ] = y$ since you are doing the inverse of the Laplace Transform on a Laplace transform.
TomB
And you can use the property of the Linearity of the laplace transform to help find the Inverse on the right, hence why you may want to write the RHS as a partial fraction
what formula for inverse of this ^
Generally, the Inverse Laplace transform is a hard procedure to do, so there is no formula for the inverse. The reason why you want to write the RHS as a partial fraction is because the 'technique' per-se is to go "Hang on, I recognise that this is just the Laplace transform of this". If that makes sense?
yep
Write the RHS as a partial fraction and I can guarantee you will recognize a Laplace transform
Not quite, what did you get as your partial fraction?
A/s + B/s^3 + Cs+D/s^2 + 2
Not quite, you should get something of the form $\frac{A}{s^2} + \frac{B}{s^2 + 4}$
TomB
You are finding the partial fraction of $$\frac{2}{s^{4}+4s^{2}}$$
TomB
which is what you want to do the inverse laplace trasform of
ok got it
$$\frac{2}{s^{4}+4s^{2}} = \frac{2}{s^{2}(s^{2}+4)}$$ makes it a tad clearer
TomB
is the ans t sin 2t?
t * sin(2t) or t - sin(2t) ?
t * sin(2t)
Barring some constants, you are in the right area
Should be the you should get something along the lines of At + Bsin(2t)
yesss!!! thank you soooo much got it
Awesome!
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@spark otter hi sorry for ping because my channel got closed
If we had $\left\langle f,g\right\rangle =\int _a^bf\left(x\right)g\left(x\right)dx$ for a set of 3 functions, in terms of axioms, why can't we extend it to all other functions in the space of real continuous functions? (defined for domain R)?
quan
because im not sure what you wrote in the other channel, im not that advanced 😔
it would help if you linked your other channel
continuity implies that the integral exists (over closed intervals), so actually you dont have to worry about what rafilou wrote
if you didnt have an integral over a closed interval, so something like integral from -infty to infty or maybe integral from 0 to 1 of 1/x, then you have to worry about the integral existing at all
yep but because this is continuous for all R
we dont have to worry about integral not existing
so it satisifes the axioms the exact same way as the original set of 3
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what is still your question
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hello
i have a simple question
find sin(2x) if sin(x) = -5/13 and pi<x<3pi/2
when i applied the formula i got a postive answer
but the correct answer is negative
how come?
for the future, send your actual problem in the first message so that it gets pinned
It seems like the correct answer is positive
what was the answer you got
120/169
do u think the book is wrong?
also do i have to take into account the interval for x
like 2pi<2x<3pi
sorry if my question seem stupid
<@&286206848099549185>
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can someone please direct me to the right direction for proving this?
if a<b and c<d then a/c < b/d
I've already studied this and my brain is just not braining I can't remember how to start proving this, it seems glaringly obvious but I forgot
are a,b,c,d real number? can they be positive/negative
yeah forgot to mention,
-10 < 1, -2 < 1, then 5 < 1?
Does this even hold then? I mean -500<1 and -1<2, but clearly -500/-1 is not < 1/2
can you show the original question in its entirety?
it's in Hebrew, I have 3 statements in total and I have to either prove or disprove them
this is the first one, so from what I understand I have to disprove it by giving an example of it not being true
you should try your best to translate them literally
yeah but now there's nothing to "teach" because we've already given you counterexamples
true
it's just a bit better if you translate word for word in terms of your learning
but it's ok
how should I have known by myself to find those counter examples?
just use basic logic and plug in numbers that I think wouldn't hold to see if I get it?
it doesn't sound true
it seems to me that the original problem has another limit
maybe it says for any positive a,b,c,d from R
there are a lot of "cases" to think about where the a b c d are positive and negatives
the main thing is whenever you do dividing or multiplying in inequalities
How do I get help solving math problems on this discord server
a,b,c,d for all R
they flip when you multiply/divide by negative numbers
Go to an available channel, this one is occupied
disproving a statement is as easy as finding a counter example
but you could also try to do it systematically
yeah, that's enough in my case
inequalities + proofs = my weakness lol
What are the other statement you have to check?
if a/c < b/d then a<b and also c>d
if a<b and also c<d then (a-b)/(c-d) > 0
well let's take my example from before
a = -500, b = 1, c = -1, d = 2
does the first statement hold for it?
oh wait
it doesn't work
let's take a = -1, c = 2, b = 30, d = 1
the first condition is fulfilled
the other are too, but this isn't enough to prove it
I'm trying to disprove it by finding a counter example
let's take a = -1, c = 2, b = 30, d = 3
now the last statement is false
I mean the second implication in the first statement
this is a counterexample making the statement "if a/c < b/d then a<b and also c>d" false
as I remember correctly to prove a statement I'd have to take a statement that's already true and then through induction I think you get to the statement that you have to prove
if that makes sense
through deduction
not induction
and yes
but it takes only 1 counterexample
to prove a statement false
right
it's easier to find a counterexample
is there a general rule of thumb kind of thing for finding counter examples?
no I just try to adjust numbers until I find something that works
Like here I just lowered d until it broke the rule
Let's try to find a counterexample for "if a<b and also c<d then (a-b)/(c-d) > 0"
let's start with a = 1, b = 2, c = 3, d = 4
I think I got the hang of it
the solution (1-2)/(3-4) = -1/-1 = 1 > 0
holds
hmmm
now let's try to break
it
when wouldn't it hold?
if the numbers were both negative
or rathr
if top was negative
and bottom positive
hmmmm....
this one might actually be true
I can't think of a counterexample
let's try to prove it them
if a<b then a-b<0 right?
so (a-b) is a negative number
same for c<d making (c-d)< 0 making it a negative number
and two negative numbers divided always give a positive which is > 0
therefore the statement is correct
I see how the logic works here, hold up I'm gonna try to write a proof for it
@broken dome is it enough to begin proving by stating "if a<b then a-b is a negative number...etc"
1 < 2, 0.1 < 1, 10 < 2 is also not true
you just look at it
and it looks wrong
hm? regarding which statement?
which one
let a,b,c,d be real numbers, let a < b, from this follows that a - b < 0, therefore a - b is a negative number, let c < d, from this follows that c - d < 0, therefore c - d is a negative number, since both a - b and c - d are negative, (a - b) / (c - d) must be positive, therefore (a - b) / (c - d) > 0
as such a < b and c < d implies (a - b) / (c - d) > 0
does this seem reasonable?
sounds fine
my proof looks something like this: if a<b then a-b is a negative number, same is true for c<d, we'll define x,y are in R+, a-b=-x,c-d=-y and get a-b/c-d = -x/-y, with the property of '-a/-b=a/b' we get -x/-y = x/y which is larger than 0
is that good enough for a proof
you didn't state that x and y are positive
I've edited it to include that x and y are positive from R, is that okay now?
oh okay
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i dont know hwo to start to compute this derivative
mr
Well here’s the thing
Notice that in the integral, the x is not the variable of integration
yh, so cant you take x out?
but how would you integrate the remaining one is what im asking, would it be a form of usub
Nah I don’t even know, but I don’t think they expect u to integrate it
would i just say using ftc this would be x(F(3)-F(1))
Yea look it’s nonelementary
lmao ive been staring at this problem so confused
Well we don’t have any function F defined
Why don’t u just leave the answer in terms of the integral
d/dx [x * integral]
oh, then would i the ingerala with bounds 3 to 0 - 1 to 0
i see thankyou for the help
:))
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Wait what
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Wdym
just splitingt up the integral first to show more working wasa done then leaving it in simplified form
Splitting it up into what? And even so, what’s the point of splitting it up if u can’t solve it
because the question is an assignment question worth 7 marks, and i alreaaday had that solution down but i thought it was too short aand couldnt figure out the integral
so i came here
Yea I mean I don’t think u can figure out the integral without some super complex Cleo method or something
So I think the point is just to leave the answer in terms of the original integral
yh, my course is onyl first year introduction to analysis with a bit of computing aswell so i dont know what tf this even was
aight
thanks for the help :))
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I'm trying to create a stochastic matrix for the snakes of ladders game depicted alongside. Does this look correct so far? If so, how would I continue in completing section (b) of this question using this matrix. Would it be following the path of highest probability, i.e., after move 1, it'll be on square 4, then after move 2, it'll be on square 5 as that has the highest probability. Or if I had to square the matrix to correspond with the 2nd move, what value would I be looking at to figure out the most probable square?
Assumptions I made were that we start on square 1 (mainly for completing the stochastic matrix for part (a) as there was no clarification), and you cannot land and 'stay' on squares 2, 6, or 8, hence, I added their probability to the square they lead to, i.e., landing on square 2 is the same as landing on square 4 so square 4 has double the probility etc.
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consider this:
The probability of landing on 5 on after two rolls is the probability of landing on 1 from 1 * probability of landing on 9 from 1 + probability of landing on 2 from 1 * probability of landing on 9 from 2 + probability of landing on 3 from 1 + probability of landing on 9 from 3 + ... + probability of landing on 9 from 1 * probability of landing on 9 from 9.
Seems an awful lot like a dot product, doesn't it?
then A^2x gives you the probability distribution for each square and you can pick the highest
Do you mean to set the values of [x1, x2, ..., x9] as [1, 0, 0, ..., 0] as part b states it starts on square 1? So move 0 would be [1, 0, 0, ..., 0], making A a 9x10 matrix?
first question yes, 9x10 matrix no
x is like
your initial state vector
with entries assigned as probabilities we start on each square
the probability we start at square 1 is 1
and the rest are 0
So I would make 2 matrices?, a 9x1 matrix [1, 0, 0, ..., 0] and the original 9x9 matrix A?
yes
So given the two vectors now, what would the approach be in getting the most probable square after the second move
I've calculated matrix A^2 as:
this describes the process pretty completely
Would I multiply this matrix with the initial state vector? So, (A^2)*(initial state vector)
yea
And then I would select the highest probability from that table, and whichever column it corresponds with would be the most probable square it'll be on after the second move?
Wait no, that would make a 9x1
Whichever row it corresponds with, i.e., if row 5 was highest probability then square 5 would be most probable?
yep

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what trouble 
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What is the missing number
5x6+5x5
use the right number to multiply the top and the left, and add them
So 55?
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Does ? Equal.
Y. W
X. Z
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Can someone please help me with question c
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hi
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yo
e= mc
suree
that is insane
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I've got the following problem for my number theory class, and I'm honestly just entirely lost. I have the result that $\left\frac{2}{p}\right)$ is 1 if $p\equiv \pm 1 (\text{mod} p)$ and -1 otherwise, but I don't know how I'd go about applying it (if that's even the right thing to do). Does anyone have tips on the right direction to follow? My class uses Burton's Elementary Number Theory, if that helps.
Corrected Latex:
I've got the following problem for my number theory class, and I'm honestly just entirely lost. I have the result that $\left(\frac{2}{p}\right)$ is 1 if $p\equiv \pm 1 (\text{mod} p)$ and -1 otherwise, but I don't know how I'd go about applying it (if that's even the right thing to do). Does anyone have tips on the right direction to follow? My class uses Burton's Elementary Number Theory, if that helps.
cat_food_sounds
have you shown the two equivalent definitions of legendre symbols? if not which way are you defining it
The definition we're using is that it's 1 if a is a quadratic residue modulo p, and -1 if a is not.
ok, have you seen gauss's lemma
yes!
I'm having a hard time figuring out how to apply it, though. (I'd assume that's probably the point of this problem tho)
yeah so
I get the general idea of using it for computing legendre symbols at least
in 2, 4, 6 ,... , p - 1, there are (p-1)/ 2 integers, and let 2k be the smallest integer larger than (p-1)/2, that is 2k is the first number showing up in the second half of the list, so we split the list up
2, 4, 6 ,... , 2(k - 1) = (p-1)/2 is the first half and 2k , 2(k + 1), ... ,p - 1 is the second half
can you see how to apply gausss lemma from here
Maybe. I'm gonna take a few to play with it
thx for not immediately telling me the answer, i rly need to get htis down myself so I dont bomb a second test
*had a small typo, fixed now

Never mind I don't see how to apply Gauss' lemma 
ok so in second half of the list, we need to figure out what happens if theres an even amount or an odd amount right
let $g = ord({2k, 2(k + 1), \ldots, (p-1)/2})$
chebyshev's infinite pee norm
can you find a nice expression for g?
The second half is the set we're considering for the sake of n for gauss' lemma, right?
correct
OK
Hm
sorry this hsould have been ord({2k, ... , p -1 })
just the size of the list
ord as in order of a set ( how many elements in a set)
okay, will leave this here if you get stuck
||the last element in the whole list is p -1, the last element in the first half of the list is (p - 1) / 2|| so the size of the list is ||g = 1/2( (p - 1) - (p-1)/2)||
now to apply gauss lemma, ||what conditions are needed to make g even? to make g odd?|| if you're still stuck ||look at what it is you're trying to prove in the first place|| if you're still stuck, consider what happens if ||p = 1,3,5,7 mod 8||
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ok so
why is 1+1=2
go read the principia mathematica by Whitehead and Russell, theres a short proof in there 🙂
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the first integration by parts is good
but after that you do the same thing but in reverse
so you will indeed be stuck in a loop
hint: x^4=(x^2-1)(x^2+1)+1
@warm dome Has your question been resolved?
Just trying the calculation ><
@zenith python so I've split it into 2
How do I deal with the first fraction
I plus 2 in numerator in attempt to make them equal or easier to integrate but I know that's no the right way to go about it TvT
first fraction is quite hard
let me suggest another way to split it :
[ \int \frac{x^4}{x^2+1} dx = \int \frac{(x^2-1)(x^2+1)+1}{x^2+1} dx = \int (x^2-1) + \frac{1}{x^2+1} dx]
LF
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Hey, just a small question. Is this a valid reasoning when finding the determinant of a matrix?
wdym by B + lambda though ?
Lambda is any scalar value and B is a matrix
it doesn't make sense to add a scalar to a matrix in the first place
I'm aware of that but we're debating a problem with a friend and he came up with that
Only thing we know is that |B| is 2
he factored it as |A(B+2)| and then split it as |A|*|B+2|
it doesn't make sense to factor it as A(B+2) for the reasons mentioned, but 2A = A(2I) so it does make sense to do 2A + AB = A(2I) + AB = A(2I + B)
I see
Help i literally forgot everything
Not to be rude but you should post this on an available channel
im sorry im new to the server idk how it works
That's alright
so do i put it in the help forum?
either in #1021175428326633542 or in any of the help channels under "math help (available), like #help-9 for example
Exactly
So, anyway, was his reasoning correct? I tried thinking of |2A + AB| as a linear combination of A but the determinant changes with 2A so it's not valid anymore
both A and B are 3x3 matrices btw
it's not wrong to write |2A + AB| = |A| |B + 2I| for the reasons discussed, but you should write it as B + 2I from the start
Alright, guess he was right after all then. Thanks again, have a great day/night!
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I need to Find the area of a segment formed by a chord 8" long in a circle with radius of 8".
do you know the formula for the segment
no
to find the area of the segment first we need to find theta
do you know how to do that @soft nacelle
can u remind me
ok
from here subsitute the known values so you can get theta
what's theta
the angle
the sin?
substitute the known values into AB=2r sin(theta/2)
ok
so 8=2* 8 * sin(theta/2)
then simplify to find theta
is u alright?
o
so this become 8=16*sin(theta/2)
then 1/2=sin(theta/2)
do inverse sin to both sides
30=theta/2
multiply each side by 2
60=theta
make sense?
yeah
ok
we have theta, and the radius
so we can find the area of the segment
lets find the area of the segment in radians
theta=60, radius = 8 so now subsitute into this
32 (60 - sin*60)?
me too
sry if not though im really bad at this
thats fine that's why we're here to help
not sure sorry
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what's the f^-1 (x) = ..guys?
do you know what an inverse function means?
i mean
yea opposite of function ig
it the x values of the original function become the y values
is there nothing else given?
of the inverse function
or do u need to find inverse of f(10)?
this is because
the inverse function is just the origami function reflected over the line y=x
@still temple Has your question been resolved?
New standard notation $Origami(f)\equiv f^{-1}$
4C
!original
Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.
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gradient function of a curve is given as
f'(x) = 16/x³ - 4.
given 2y - x - 6 = 0 is a normal to the curve,
find equation of the curve.
i think i found the answer but i'm not sure if the method is appropriate
find slope of the given line , and we know that
if they are normal (aka perpendicular) slope 1 * slope 2 = -1
oh wait nvm i read the question wrong
and i plugged x = 2 into the equation
integral = normal
and got C as 14
14 is correct but not sure how it works
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Is my answer correct?
@devout mist Has your question been resolved?
@devout mist Has your question been resolved?
Yes that's correct
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Hi! I was wondering if anyone has any idea as to why they have taken f(x) as dy/dx equation and not the y equation?
where, wdym
So as you can see in the question (left side) they've given a y = equation and then its derivative
so for newton raphson i assumed x- (y = (x-5)lnx / 1-5/x + lnx)
subbing in 2.4 for x
they're trying to find the location of the turning point
but they've used the first derivative as f(x) and then got the second derivative for f'(x)
which is what im confused about
so they're interested in when dy/dx = 0
so is that then what you do when its a turning point? f'(x) as f(x) and f''(x) as f'(x) ?
essentially you're trying to approximate when
1 - 5/x + ln(x) = 0
starting from x_0 = 2.4
ah okay so in newtons method we need f'(x) = 0
and since in this case it doesnt and the derivative does we use that instead ?
bcs when finding stat. pnts dy/dx = 0 ?
they used f(x) to represent the function you're trying to find the roots of, not the derivative of the original y
but what they've set as f(x) in the markscheme is what it says is dy/dx in the question tho
yes
so because its a stat point we use the derivative hence them setting it as f(x)?
that's what i'm saying, f(x) isn't y here
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give me a sec
no thats against the rules
are you sure? it practically is what you need to solve this
lmao my problem is i did the tree diagram wrong, but i cant find a way to change it to make it right to get the answer
then show it
this is def wrong but i used diff numbers several times but i keep getting funky numbers
what are those numbers on the top right branch
wait hold on how this is against the rules?? (isnt this server to help with assignments that you cant do or smth)
4/7 (red), 4/7(blue)
you misunderstood. It is to help guide you to solve it yourself. Doing the work for you is what's not allowed, meanwhile
yeah i get that, i need guidance to get the right tree diagram
idc bout to answer i wanna know what i did wrong
Wait why exactly are you getting 7 in the denominator by the way? you are excluding a ball, not two. So why the jump from 9 to 7?
2 further draws are made without replacement
right but its like
you start from 10 and pick a ball - > you end up with 9 so u pick up a ball - > you end up with 8 so u pick up a ball
so all in all 3 times
you overshot it by 1
to put it in a better way, you should label the edges of ur tree diagram with the probabilities and there should be 3 of them in total
something like this
yeah so i think u r fine with just replacing ur denominators with 8
and that should make ur thing hopefully right
aight good luck! sorry if i seemed confrontational earlier
lol its ok, have a good day!
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Hello good people I have a problem regarding Sequences.
Sum of all terms of an infinite geometric sequence is equal to 24 The sum of its terms with even numbers is 8. Calculate the first term and the quotient of this sequence.
I have translated that with the help of google so there maybe a misunderstanding but hopefully there isn't. The answers should be a₁ = 12 and q = ½
I need help with an electrical engineering assignment, i dont understand the math used in the solution.
What is the formula of the geometric sequence?
And what does "sum of its terms with even numbers" mean?
That answer is correct. Are you asking how to work it out?
1 sec
that's literally the whole assignment
it only says word to word: Infinite sequence (an) is equal to 24, and it's Sum of even numbers is equal to 8
nothing more
After looking around I only found this formula
If you write down the sequence of even terms, you will realise that this is itself a geometric sequence:
ar, ar^3, ar^5 ...
So you can work out its sum the same way as any other geometric sequence.
oh by using y^2 = x * z ?
Oh even terms, I thought the terms where the value is even.
Plug in the formula, then.
yeah but what will plugging the formula give me when i have no numbers at a1 or q
oh wait this one
Yes, and you don't have to plug in a number.
to the both of these?
Yep
that looks hella weird
oh wait looks like i made a mistake there
idk I've done something but It gave me 1 instead of 1/2
Wait:
$$8=\frac{a_1}{1-q}$$
Xwtek
That doesn't sound right.
Yeah that was supposed to be the Sum of equal numbers
In the sequence that sums to 8, what is the first element in sequence?
Definitely not $a_1$
Xwtek
And what is the ratio of the adjacent elements in a sequence that sums into 8?
And from now, it's trivial to obtain $q$ and $a_0$
Xwtek
عذراً، لم أفهم ما تقصده.
عذراً، لم أفهم ما تقصده.
عذراً، لم أفهم ما تقصده.
عذراً، لم أفهم ما تقصده.
English please?
He said he doesnt understand
idk
thanks anyway m8
still got 21 more to do
I will come back soon I guess lol
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there is a lot of terminology in those images
00
that seems right to me
i think you'd prefer to use strong induction here
you don't know how big Y is but you know it's strictly smaller than X
it'll work but it means you end up writing a huge paragraph
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Would multiply both sides by (b+rd)(b+sd) first, since it's clear that this product is positive it won't invert the inequality
The latter
You'll end up with something like
(a+rc)(b+sd)<(a+sc)(b+rd)
(a+sc)(b+rd)-(a+rc)(b+sd)>0
I think some terms cancel out there when you multiply
I subtracted the left side from the right side
I'd say just multiply them, you'll get
(ab + scb + ard + scrd) - (ab + rcb + asd +rcsd) > 0
The first and the last term cancel out
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,rotate
#4, how do I start
First find the radius of the circle
The area of shaded region is the total area - area of rectangle
Ok then find the area of the rectangle
Is the radius of the circle the same as like CD?
No
How would i relate the radius of the circle to the rectangle
Okay so AD is 5
Yes
Now AC is also the radius of the circle
We have AD and AC, by Pythagoras thereom, find CD
Yep
So what is the part of the circle above BC
Nevermind
That is part of the 90 degree sector
Thank you bro
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What am i doing wrong?
$$A = \M[ 8 1 ; -2 6]$$
$$x^2 - 14x + 50 = 0$$
$$(x-7)^2 = -1$$
$$\lambda = 7+- i$$
$$(A- \lambda_+ I) = \M[(1-i) 1; -2 (-1 -i)]$$
$$(A- \lambda_+ I) = \M[(1-i) 1; 1 (1 +i)/2]$$
Book Reader
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Hi
hi!
<@&286206848099549185>
My question is just why they put log a why the •a•?
Is it because we can put anything we want in the place of b?
This is the formula can anyone help?
its log base 10
No no we only use letter we prove that the left side is equal to the right side thats the exercise
?
Yes
We have these formulas
Not sure if u can read it but the bottom one states that we use log b/ log b
But they used a instead of b why is this?
.
Yes, that formula works regardless of the base of the logarithm
They could have used anything, but by using a, they get log_a(a) in the numerator
Which is equal to 1
Oh right so we can use anything? Alright
Yeah, the base can be anything in that formula, it just has to be the same in both the numerator and denominator
Notice on your formula sheet, they started with log_a(x) and they used a generic base b
But do we constantly work out the whole equation like how do we know its gonna equal what we want to?
For like a long exercise how do we tell what is best used in the place of b?
It probably won't matter most of the time
Wdym is there no way to tell whats best used in that place?
I mean, there's all different kinds of problems, so I guess it kind of depends on the situation
but like in this case, you didn't have to use a
You could have done something like
This situation lets say? We just got introduced to logs so
$\log_b(a) = \frac{\log_c(a)}{\log_c(b)} = \frac{1}{\frac{\log_c(b)}{\log_c(a)}} = \frac{1}{\log_a(b)}$
tatpoj
Even with a different base, it's still not too complicated to get the same result
Euler?
yeah usually I'd just use e, but I just used a generic base c here
The base doesn't actually matter
it's the one from the bottom of your sheet here
Ye the first part bu what about 2nd part?
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np 👍
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is dis alright
Uhh this is hard to read 😭
Can you send the original problem
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Hey all need someone to do a math check on a really large piece of math
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<@&286206848099549185> c;
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what defines if something spans over R2 or R3
it spans "a set in R^3"
but say you had a set of vectors
what would define if it spans or if it doesn't
every set of vectors spans some vector space, the question is what vector space that is
What I had previously understood it to be was
they can't be scalar multiples
of eachother
and they can't have a 0 vector
this doesn't fulfill the second criteria
that's (part of) the criteria for being a linearly independent set of vectors
the set doesn't have a 0 vector, idk where you got that
is the z value not a zero vector?