#help-0
1 messages · Page 826 of 1
choosing a point where the function switches makes it easy to split the integral into 2 parts
it doesn't make sense, we are to get b_n, and the functions intervals is given above, I mean can we choose intervalls that exceeds the boundary?
the function here goes on forever
you just want an interval that's the length of the period to integrate over
and how is -1 the length of the period?
it feels weird i can choose the starting point random
some people uses pi and some not
so like the function repeats with length 2 right?
yes
the fourier formula you posted is an integral of length 2, so no matter what d is, you're adding up each point in the function once
Can someone help me with #16
but don't d represent intervall on the x axis, on the bottom it doesn't add with length 2
@sweet marlin not done yet
K
not sure what you mean
when you plug d=-1 and T=2 in it's an integral from -1 to 1
which the question gives f(t) for
then the integral is 100 to 102, which gives the same a_n's and b_n's
oki I see, but is it good to choose d = 1 ?
that's fine too
either way you're going to split the integral into f=0 and f=1 parts
normally I'm used to have negative on the bottom of the integral
but it doesn't matter
I know the channels busy plurmorant when you’re done here can u come to channel 5?
@charred flint but let's say we have -1 to 1, which function should I insert, 1 or 0?
what is f(t) in between -1 to 1
well it's 0 then it's 1 as you go along
to do the calculation you split up the integral from -1 to 0, and 0 to 1
but with -1 to 0, the function is 0
and integrate of 0 is 0
so we can skip -1 to 0
and focus on 1 to 0
@charred flint but this would only have worked if you actually chose -1 it would have worked if you used d = 5
any d will do the same thing yeah
sure
and 5 to 6 has f(t)=0
and the integral will really be from 6 to 7 with f(t)=1
what part don't you believe
so first of I don't think you can split 7 to 5, into 5 to 6 and 6 to 7
yeah but how can you split 5 to 7, into 5 to 6 and 6 to 7
that's how integrals work idk what you mean
oh
yeah
my bad
yeah you can split into functions like that
okay but how is 5 to 6 has f(t) = 0
so the question says -1 to 0 is f(t)=0
yes
it also says f(t+2)=f(t)
so we can shift those numbers up and down by multiples of 2 and it still works
so -1 to 0 is 0, 1 to 2, 3 to 4, and 5 to 6...
the reason why I'm so confused is because they are not negative numbers, but I just forget it is just periods that repeat it self. it is just odd that it repeat it self on positive x axis
right
but it is about the inter vall not the x axis perse
but what if we had three conditions on the picewise what would we have done? then split integral into two pieaces would have done it ?
for piecewise you split it every time the function changes yeah
huh
when you have a integral that has a intervall, you are ought to substract when you put these values in the inte finnish product
nvm yes you should put it in t
so for an example we have the integral -1 to 0 and we are to integrate cos(wnt)
and we get sin() and now we are to plug it in and we get
sin(1)-sin(0) = -sin(wn)
does this mean a_n = sin(wn) ?
-1 to 0 is 0
Integral of cos is?
sin
sin(1nw)-sin(0nw)
Got it?
Yep
Waiting
How much is n
infinite
What about for a_0
Sub in 0 instead of n yeah
but then we get sin(0) = 0?
Is it a problem?
no, but then we only have the sum
but how are to deal with the sum I forgot about it
so we have sum( sin(nwt)* cos(nwt))
what are to do with the sum should we leave it there
can i quickly ask how does multiplication work with roots? (like is 2* sqrt(16) same as sqrt(32)?
Nop
@alpine sable
then how does it work?
because i got the answer (2-sqrt(32))/2
and it says the final answer is 1+2sqrt(2)
Hey, can anyone help with trig functions and triangles?
What channel can I go to rn?
Dunno, depends on what the problem asks I guess
Yeah leave it in that form
and we wouldnt leave in that form what would we do then?
it wants the fourie series
That's one of the "common limits" too
@sturdy grail check how it behaves for a_1, a_2
@alpine sable ah really that ez?
Fourie series got abit easy to understand now. thank you
I don't understand why I would need fourie series in EE
rn we have signals and systems
a_3 etc. What you usually get is certain behaviour for odd or even values
You'll see when you get to fourier transform, laplace
I know about laplace transform
what is it you transform in fourier?
@alpine sable derivtate demoniator and numerator
but if you get wishy washy answer, then you should use taylor formula
inotherwords if you get complex dneominator and numerator you should go with taylor formula
Epic while he searches can you check questions 1? Quick question should only take a few seconds
@sturdy grail you transform time domain functions to frequency domain
is the blue frequency
Yes
why would you want that
For filtering
For example, I only want the low frequency. I make a low pass filter. The freq domain helps me see where the cutoff mark is
what effect does low frequency have on that square wave?
Filters out the ripples in the high and low parts of the wave for example
Yes, just an example
Explain
the more constants we have in our fourier series, the more we can replicate the function ie, that wave will smothen out @alpine sable
I don't think I've worked with rienmen sum I think not sure. I'm not so well versed in that sorry.
Np
@alpine sable can I dm you? do you study EE too?
I finished some time ago. You can
you graduated?
what do you work as?
Technical writer and tutor in my free time
Em could u take a look at my question?
Who good at algebra but with graphs
@raw shard are you online?
@hybrid plume yes
@hybrid plume sorry i don’t really remember anything about riemann sums
Np, do you know any helper who would?
you’d honestly be better off just looking it up lol
no i don’t
i would say just post it and wait for an answer
@sweet veldt neither, scientific notation is x*10^y, where y is an integer, and x is an number between 1 and 10
so this is my problem right? 2.710^4-3.710^3 correct?
so i have to bring the 2.7 to 27*10^3?
@raw shard
do i leave it that or make it 2.33*10^4
okay sorry im not familiar with the commands
but also because it was originally 2.7*10^4 correct
hi <@&286206848099549185> , is there any way to prove that {NOT, AND, OR} is functionally complete?
it means that you can construct every boolean expression with binary operands using just those three operators
operands meaning the inputs to the operator
well the idea is that you don't need any others
just AND, OR, and NOT
because XOR is just ((P OR Q) AND NOT (P AND Q))
but im trying to figure out how to prove that this is the case
no worries
i mean
the answer is x >= 9
yeah
rewrite the expression as sqrt(x - 9) >= 0
because it is guaranteed that the principle square root of any quantity must be nonnegative
how would i construct the proof tho
would i start with an arbitrary truth table of size n
no no no
im asking how would u start the proof
idk what i can assume
what would that look like
ye
so for an arbitrary expression T(p1, p2, p3, ..., pn)
T is logically equivalent to the DNF of every case
right
Yeah... cause sqrt maps to non negative numbers
So it's just the domain
every case where T(some input set) = 1
not sure what your saying
all i know is if i square both sides it eventually equals x>=10
which is incorrect
no
right
so its also sqrt(x-9) >= 0?
so we know for a fact that the set of numbers in [-1, 0) is not in the domain
so we can ignore them
this expression is equivalent yes
Oh oh
because of the domain restriction of the sqrt() function
i see
Which I the same as just the domain
a square root can never be a negative
ye
gotcha
is this channel free
Done
I need to know how to actually do it on my own so when I have a test I can do the question
pls
Is 5x the x value and 2 the y value?
but it doesn't give me the rise over run thing so idk where to plot the other points
Where did u get-1 from
I picked it. You can pick any numbers
Why
the ...x number is the slope
and the number after is the y intercept
It's domain is over the whole set of real numbers. It exists for any value. Whatever x i give it, i get a y back
if you have a line with a slope of 5
then
for each unit of x there are 5 * x units of y
so
if you move 2 x
you move 10 y
good so far?
Our methods are different. Choose your path
why must math have so many paths
Mine is better
Choose any 2 numbers elon musk
tf
3,8
hELP
Oh
if you have a line with a slope of m, then for each x-position unit you move along the line, you will move m*x y-position units
13,38
you are wasting more time than u need
the y-intercept just changes the starting y-position
First point is (3,13)
Second point is (8,38)
@bold mantle
Find those coordinates and put dots there
and for each x-position unit you move 5 y-position units
Ok
Take ruler and connect them and extend the line in both directions
Mhm
Now, if you picked 0, 1
It would have been easier to draw and calculate
Makes sense?
Ok
You pick the numbers that work easier for you to calculate and find on plot
Would u mind doing f(x) = 6 for me, step by step, I learn well that way
Plot the function f(x) = 6?
graph the linear function
Ok
oh ok
another method you can use is just graph two different points of that function
and make a continuous line between them
My method yes
Could you do f(x) =3/4x - 2 please
1
How much is y
2?
,rotate
Couldn't find an attached image in the last 10 messages.
,graph 5x-2
ok here
,w plot 5x-2
Ok
Thanks but I can't read it lol 😦
this channel is done?
why is it not c?
im guessing because it reaches to the 25 and 4 ?
How to not procastinate
Hello, 25 and 4 are the squares of both semi-major and semi-minor axis, respectively
how do i find the relative minimum?
2 was super specific
everythign around it was positive
so i couldnt pin point it was 2 but after guessing and checking it worked
is there a way to find out that is is 2
Random question but am I doing this right?
6^5 x 6^-3 = 6^5 / 6^3
yes
is there a hypothesis in a maths report?
Can anyone help me with this question
Question 13
I tried but I am getting DNE
The correct answer is ||-8||
I googled and found this
But I don’t understand how did they simplify
Anyone?
They factor x-2 out of the numerator (so it cancels and remove the problem when x->2)
Hmm
@past sundial Yes
@quartz osprey If you graph the equation you should x = 2 as your relative min then.
In order to locate any relative minimums/maximums you need to graph the equation first.
this is without graphing iirc
@quartz osprey If you don't know how to solve the polynomial, here is a video that should help https://www.youtube.com/watch?v=HKDdzBuffoY
This algebra 2 video tutorial explains how to factor higher degree polynomial functions and polynomial equations. It shows you how to factor expressions and equations in quadratic form using substitution. It shows you how to factor cubic polynomials using the factor by grouping method and how to factor special cases such as difference of squar...
what is iirc?
How did your teacher do it? There might be other ways my bad
if I remember correctly
oh, thanks
@quartz osprey or this is the other way to do it or that you might be doing https://www.youtube.com/watch?v=WCq3sRzsJfs&t=73s
This calculus video tutorial explains how to find the local maximum and minimum values of a function. In order to determine the relative extrema, you need to find the first derivative, set it equal to zero, and solve for x which represents the critical numbers of the function. You need to put these numbers on a number line and create a sign ch...
Andreww
Ahh ok
oh no i already solved it lol
it was -2,0,2
the thing was that -2 was- 0 and 2 were both +
i couldt pinpoint the exact location it was a min or a macx
min
cuz as you know it was _ + +
how can I turn this displacement over time graph into a velocity over time graph
one sec
Was i correct
Random question but am I doing this right?
10^-4 x 10^5 = 10^5/10^4
yes
Okie thanks!
I dont need help anymore by the way
sorry i got lost thinking about something else i think your right
cool
guys, I think i'm over thinking this one... how does the 24 become a 4? is it simply because it's being divided by 6?
yea
thanks man
just needed to make sure. a beautiful subject but holy crap it makes you overthink to an unnecessary degree at times
ye
i mean just ignore constants right

dealing with variables
'some constant' times the important part
once you got the variables you can go back and get constants anyways by letting vars be some convenient value
it's just algebra at the moment. hoping to get to calc at some point. wait... maybe what i'm learning is used in calc idk yet
how do i find the critical points?
i know its 0 and
idk how to find the other number
other?
theres no way its just 0
oh, its not 0 i mean
your original function isnt defined at 0
so thats gonna be a problem
critical points will come from g'(x) = 0
yea im finding the critical points or where the derivitive is not defined
critical points are not where the derivative is undefined
can u not post your q after mine was unanswered lol
oh 
its fine now cuz ur getting help but its just bad ettiquette
u gotta use the ratio test
yeah I tried that

it didn't yield anything

Isn't it also when the function is not differentiable? Which in this case is when the original is undefined?
it does?
im not sure
oh idk
bru
harder than the alternative
wait nvm
4x^3-864/x^2
I did, you can see in the third image I sent
okay 
r tends to infinity
<@&286206848099549185> still stuck
take it back 1 step
can you guys go to like
youre looking for when the function is either not differentiatable (original is undefined) or when the differential equals 0
8 maybe?
yeah nws
im curious about kuramas

Need help on how they got the unit Run
if someone could explain this to me i would appreciate it
i know my answer was wrong i chose a random one
i just didnt know how to solve it
is anyone here able to help me with a linear algebra problem
Just post the problem. If someone can help, they will
remember f-1(x) is not 1/f(x)
Could someone explain to me how this is (k-1)ak+ak derived from the question?
its f(x) reflected across the line y=x
or, when f(x) has its y and x flipped
hence, g(x) is equal to f(y) at point x
how do you generate an equation using the bot in here
nvm i solved my own question
suppose that g^(5005) is just an exponentiation
just find g(-3pi/4) and raise it to the power of 5005
hey waler would you be willing to help me with some lin alg work
just post it in an unoccupied channel
Is that how this works?
but sometimes f^n(x) can also be used to notate f(x) is compound in itself n times
tho if it really does mean f(x) is compounded in itself n times, then theres probably some kind of theorem here
or maybe some cancelation in g(x) that can make the composition really easy to solve, but i cant see that for now
yeah.. we're in the derivative unit
eh no, this has nothign to do with derivative
So A = LU and we want to solve LUx = b
What's the solution to Ly = b?
Once you have that, realize that Ux = y, and solve that
can I know whether |AB x AC| = |AB| x |AC|
and if so, why?
cross products and vectors I am talking about
hiiii can someone pls explain why the 6xyz turned into 6yz & 6xy(dz/dx)?
may I ask
chain rule when differentiating w.r.t. x
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I heard google.com knows
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Or Wikipedia
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bruh
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you’re trolling
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2730/10 if you wanna be sophisticated
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ah just random troll
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now i know for sure you’re a troll
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no
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yes
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both of those are integers
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the numerator and denominator must be integers
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idk why i’m replying to you, you’re a troll
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, the set of rational numbers (\Q) is defined by
[ \Q = \left{ \frac{p}{q} : p, q \in \Z, q \neq 0 \right}. ]
ricey
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yuh
if they don’t know what a rational number is they won’t know what that means @hardy gulch
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im struggling with this question , can someone help please, thx
i presume direct proportion means that x^2 = ky for some constant k
@late kernel So x^2 is proportional to y. So if x is doubled, (2x)^2 =4x^2 so y is multipled by 4
How would I do an epsilon n proof for $\frac{3x+3}{\sqrt{x^2+1}}$
ALBERTO BALSAM
ohhhh
ok i understand now thanks alot dud
np
what are you trying to prove?
that it approaches a specific value?
Yeah, sorry meant to put n instead of x, I want to prove it converges to 3
Ryuzaki
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
Ill rewrite it
Can i define a mathematical point as a hypothetical geometrical figure having no width, thickness or length i.e x=0,y=0,z=0?
Ok
ALBERTO BALSAM
How do i solve this Im helping a friend
@white kiln See what both numbers are divisible by. 18 and 24 both are divisible by 6 and 3. Use the highest one so you don't need to reduce it more.
u got your solution in other chats so ill assume i can ask here
can sb pls help me w this
i got 2880 lol
i drew the pentagon and counted the number of possible cases each vertex so 6x6x5x4x4=2280
can sb pls help me ;-;
shouldnt it be 6!
6 factorial
oh wait there are 5 corners nvm
wait it should still be 6 factorial
There are $6$ colors to choose from, and the ends of each diagonal must have different colors
kk9
thats the problem ;-;
by ends of the diagonal you mean the corners right
ok
so for one corner
you have 6 options
second corner you have 5
third corner you have 4
and so on
that just becomes 6x5x4x3x2
hmm
but that becomes 720
and that isnt an answer
yeah :'(
interesting
i dont understand the explanations
There are $6$ ways to assign a color to $A$. WLOG, give vertex $A$ a color; we can multiply by $6$ at the end. Since vertices $A$ and $C$ cannot have the same color, there are $5$ ways to assign colors to vertex $C$. Using this same logic, there are $5$ ways to assign a color to vertices $E$, $B$, and $D$, giving a total of $5^4=625$ ways. However, vertex $D$ cannot be the same color as vertex $A$. To use complementary counting, we need to find the amount of ways for $D$ and $A$ to have the same color. Notice that this is equivalent to the amount of ways to arrange colors among the vertices of a square. Using the same logic as above, there are $5^3=125$ ways, except we must subtract the number of ways for a triangle. Each time, there is $1$ less vertex, so $5$ times less ways to color. This process stops when there are only $2$ vertices left; in this case there are simply $5$ ways to color this figure. So in conclusion, there are $6(5^4-(5^3-(5^2-(5))))=6(5^4-5^3+5^2-5)=\boxed{3120 \ \mathbf{(C)}}$ ways.
kk9
OHHHH, i thought every corner must have a different colour
so how can we solve it? :p
but its just that the ones next to it cant have different colours
so how can we do this ;-;
hm
😭
sure
Each vertex of convex pentagon $ABCDE$ is to be assigned a color. There are $6$ colors to choose from, and the ends of each diagonal must have different colors. How many different colorings are possible?
can sb pls explain this ;-;
kk9
yeah
B cant have the same as E and D
yeah but im stuck on how to find the total possible combinations
same 😭
i suck at math
i always get stuff wrong at casework so i rather not do it
can sb pls explain solution 3 ;-;
hi
anyone?
solve for tan A using quaddratic formula, then use trig ratios?
Can you calculate definite integrals using only arithmetic?
u can approximate it with numerical methods
Some, yes. See Guassian quadrature
when u add an edge, u add a pair of vertices right
thered be a connected component when neither of those vertices are contained in the subgraph i think
does it say G is connected
why would u construct A that way
whats the context
Oh
well even if A is connected, adding vertices that arent in A but are in G would create a connected component right
yeah
but if A is connected, that doesnt imply that G is connected right
you could add an edge that isnt connected to A
wdym
well udk if G \ A is connected either
Is this channel free?
help anyone?
Can someone help explain this question to me? I solved everything correctly besides the part about additional material wasted on support structure being 14% i’m not sure whether to add 14% of the weight or take it off. And if i add it, from where do i find the 14%?
X=0 Y=0 Z=4
ok
you'll have to explain to me every part of that question
Which one of us? >.<
Sorry I didn't saw his question D:
Yeah so the weight i got of the finished product is 2.897kg, then i added 0.33kg to it from the CNC machning bit which adds up to 3.227kg. What’s left is the 14% additional material wasted, how do i find out what value do i get 14% off to add
it's fine, I just don't know what m or Decoder are
idk what the CNC bit is because I can't see question 5, but the answer is just adding the normal cost plus 14% of the material cost extra
Oh so like if the final cost is $4500 i multiply it by 14% and then add 4500 to whatever that value is?
Final cost is for the raw material before any machining
sounds good
But we don’t know what the weight of the raw is
Can someone help me to solve: arcsin(sin(10pi/9))? It has to be an exact value and we can't use a calculator.
Use the unit circle
10pi/9 isn't on the unit circle though...
Make it appear on the unit circle
use the definition of arcsin() and property of sin() i.e. sin(n*pi+(-1)^n*x)=sin(x)
Oh, wait, it's divided by 9
Guys what is 4+3
I'm serious
definition of arcsin() is inverse function of sin(x) for x in [-pi/2,pi/2] btw
Then use a calculator
Okay so what's the square root of 980
Use a calculator
Baguette I hope you find something better in life I wish you nothing less
Ok
shit i'm not mentally okay
What would n be in my case?
you're gonna have to decide that based on the restriction of domain of sin(x)
(restriction is [-pi/2,pi/2] so you would want your input to be something like arcsin(sin(a)) with a in [-pi/2,pi/2])
Guys need help with my pre calc
Can someone hep me with this
everything.
lmfao
i figured it out after a bit, thanks
Does there exist a 3x3 invertible matrix A such that $BA^T=A^{-1}C$ where B and C are are arbitrary 3x3 matrices?
ALBERTO BALSAM
lmao
just giev me the damn answer my parents are not gonna pay for my tuition if i dont pass the test
4
is there context to this because ABA^T=C just gives you a matrix C for any matrix B of you choice
common
no
its 3 in the damn morning
i have a test in 5 hours
i havent took notes and studied at all
frick my parents are gonna kill me
ffs
i told them i got a perfect score on my last pre calc longtest
the truth is i failed
i got 47%
ffs
lmao
I know you're trolling but if you lied about your results and actually feel guilty you can use that energy to redeem yourself, I have done it more than once
your plan depends on others helping you out so I wouldn't say you learned your lesson even if it was academic dishonesty but sigh 😕 you are not going to get help here when you phrase it like that
its my parents fault
i want to be a damn lawyer not an engineer
what a waste of tuition money man
if they are more blatant about cheating on a test even if it as a joke I would ping mods but I am 99% they are trolling cuz last time they asked a fractions problem and now they're on some basic calculus within 2 days
XDDDA
sigh.. im just gonna drink hotdog juice after the test bye
.
iam not trolling wtf ...... i only troll on valorant
XDD\
iam kinda wasting my time when i waste ppls time
they left 
i'd rather you let us know of your suspicions (can be by modmail if you prefer to keep it private) instead of sitting on em
I mean to ask given any two symmetric matrices, is there some choice of B such that it always holds?
Is this question a typo?
How do you get cos(2x)=1? The triangle wouldn't exist, right? You would just end up with a straight line
@river remnant I'm lost on what you're asking
the question is giving me cos(2x)=1
yeah, I'm lost on why you're asking about a triangle being a straight line
but cos(any angle) shouldn't be 1, because the triangle wouldn't exist, right?
x=0, x=pi, x=2pi
when x=pi wouldn't it be -1 not 1
no, because it's cos(2x) not cos(x)
which means the period is 2pi/2
anyway yeah cos(x) = 1 means it's not a traditional triangle but cos can still equal 1
remember cos is just the measure of the ratio between the adjacent and hypotenuse
or x/r
and that occurs on the horizontal line portions of the unit circle
yeah thanks
ALBERTO BALSAM
x^2 divided by 7x^2
anyone?
how would you solve
5x
x
@remote silo
also yea sry i dont remember enough lin alg to help :(
yeah i mean, how would u simplify that
i'm also asking that as an example for him, not a question
@remote silo But yeah,
5x^2?
yes i know
5
how about 5*2 / 2
you can either evaluate that as 10/2
OR you can cancel out the 2s on the numerator and denominator
and get the answer, 5 right
yeah
so how about 5*x / x
still 5x?
why x?
look at the 5*2 / 2 example we did above
just think of x as a number
because that's what it is
it's just some arbitrary number, it's not anything too complex or different
so its 5?
yes, you just cancel the 5 term from the numerator and denominator
so how about x / 7x
7
-7?
14/21 or 21/14?
what..
14/21
if you scale the numerator of a fraction, and scale the denominator by the same number, then the fraction has the same value
so what is the highest common factor is 14 and 21
i think you gotta really brush up on basic arithmetic skills before moving onto / continuing in algebra
can you help on multiplying and dividing rational expression though?
@remote silo what is 2 /( 2 * 7)
especially if whatever you want to do in the future requires further mathematics you'll struggle a lot at this rate, it'd be in your best interest to go through various lessons from sites / youtube channels
7?
@remote silo if you are unable to simplify 14/21 or 5*x / x giving you the answer to your question wouldn't help you at all
no man
just cancel the 2's
and your left with 2/2 on the numerator
which is 1
and (7*2)/2 on the denominator which is 7
so you get 1/7
i really can't see why my solution of y=4x/3 + 5/3 is incorrect, ive been stuck on it since last night, could someone share some wisdom
What is the chance of a 1.4% thing happen twice in a row
@north blade (1.4%)^2
(0.014)(0.014)
0.000196%?
no, this is the raw probability between 0 and 1
if u want it back into probability u need to multiply by 100
oh yeah
it's like how P(A) = 1 means there is a 100% chance of event A occurring
<@&286206848099549185> can someone explain why my answer is incorrect im so lost.
i even changed the syntax of the equation to 4x/3 + 5/3 since it was incorrectly written in my answer
Was wondering if someone could help me figure out where I was a big stupid dumb idiot.
I first differentiated the function between f(x) and g(x)
and their primes, one using power rule the other using chain rule
then I utilized product rule to put it into this equation
(second writing out their derivatives)
No need to consider -2 as its own function
Constant multiple rule: Take the derivative as if the -2 isn't there, and throw it back on after
d/dx[-2f(x)] = -2f'(x)
The product rule will work and get you the same thing
yeah so my issue was actually that I didnt use chain rule on g(x)
instead I used power rule and completely forgot about the 1/2
so I ended up with an extremely similar answer
<@&286206848099549185>
I see what I did wrong while explaining what I did, and thanks for the advice
I keep neglecting that constant multiple rule exists
thanks!
Could someone give me a hint? I know how to simplify this sums without the 5 * in front but not with it.
yeah sure i could but is it possible to simplify two sums when i have a factor in front`?
You can combine the two summations into one
It just means "compute the sum, then multiply it by 5"
Notice I gave that part explicitly
nah not with the 5 in front
then my thought was wrong, thank you
will try it now
it was correct
$5 \cdot \sum_{k=1}^{3}\left(1+\frac{3}{5} k\right)-\sum_{k=1}^{3}(4+4 k)=
\sum_{k=1}^{3}\left(5+3 k\right)-\sum_{k=1}^{3}(4+4 k)=
\sum_{k=1}^3 (1-k)=-3$
秋水
can someone explain why my first answer was incorrect, ps i changed the notation so now its 4x/3
maybe should be written as 4*x/3
yea i had changed it
to 4x/3
still incorrect
ive been stuck on all last night and all this morning
do you have *
wow so i can really just multiply the frontfactor with the sum?
yes, like k*(a1+a2+...)=ka1+ka2+...
thx man
Can someone help when youre done
im done
You just need to calculate the distance from the origin to the line
Or you combine the two equations and then the two real roots of the quadratic equation are equal
Eh
$x^2 + (-3 x + 10)^2 = 10$
秋水
What do i do from there
Expand?
Is that what im meant to do
But if i find x what do i do eith it
$(-3x+10)^2=9x^2-60x+100$
秋水
not 9x^2+100
Huhhhh howd u get that
$(a+b)^2 = (a+b)(a+b) = a^2 + 2ab + b^2$
egg bird
Okay now what
Find x, find y
Then since one point from the line touches the circle, it must be a tangent
Is x 3 and y 1
Yes
Say that since the line and circle intercept at just one point, it must be a tangent
Okay thankksss
Found it!!!!!
Same though
I thought I did this correctly
is there any chance I screwed up somewhere else I didnt notice?
yes, you are correct
秋水
