#help-13
1 messages · Page 204 of 1
well whats 1^3 and 1^2
1 and 1
A+B+C
okay
so f(1) = A + B + C = 4
you need two more equations
so you need to repeat this process twice more
what do you mean repeat
with a diffferent x from the table
like do the same thing with a different x value?
yea
sure
what do I do after I get F(2) = a(8) + b(4) + c(2) = 20
that 8a + 4b + 2c = 20
would that be the second equation?
yea
so I go onto the next x value?
yup you need 3 total
nice username 🤔
i dont remember
hmm the graph doesnt look right
what dyou get like first a+b+c=1, then 8a+4b+2c=20
what do you mean
64a+16b+4c=136
like what did I solve for first?
no
when I check my a b and c values im getting 4=4 20=20
does that still mean im wrong
whats a matrix
well when you get an a b and c
you can just graph your answer
and see if it works out or not
these system of equation things are pretty error prone
alright
lemme see
i mean you could solve the first one for ... lets say c
c = 1 - a - b
the nyou can substitue this into the next equation
yea I did something like that
so 8a + 4b +2(1-a-b) = 20
or 8a + 4b + 2 - 2a -2b = 20
or 6a + 2b = 18, i think?
say 3a+b=9
so b = 9 - 3a
shouldnt it be c=4-a-b
here
sorry
lol youre good its not your fault
so c = 4-a-b
and 8a+4b+2(4-a-b)=20
so 8a + 4b + 8 -2a-2b =20
then 6a + 2b = 12
or 3a+b=6
so b=6-3a
then we had c=4-a-b=4-a-(6-3a)
or c = 4-a-6+3a = -2+2a
lol this stuff takes so long
last one
64a + 16(6-3a) + 4(-2+2a)=136
,w simplify 64a+16(6-3a)+4(-2+2a) = 136
a = 2 
I got that
ive made a mistake somewhere im sure of it
oh
OH
its right 
you were right
i was wrong
sorry man im just so god damn tired
so f(x)=60?
thank you for the help
no problem thanks for bein patient with me
@olive folio Has your question been resolved?
Closed by @olive folio
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hi, can anyone help me with this
!occupied
Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).
i tried finding the limits and they gave me 0
weird defn of "differentiable" they got there.
the limit of f'(x) should not have given you 0. show work?
ok
Thats the first part
im confused about the whole limit to 0- and 0+ thing
because both of these just equal 0
to prove its continuous
@umbral mirage Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
@remote moon Has your question been resolved?
Closed by @remote moon
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
you know the formula to calculate arc length of a function?
We use the formula
$L = \int_{a}^{b} \sqrt{1 + \left( \frac{dy}{dx} \right)^2} , dx$
Jane
yea this makes sense
but then why do have to find the antiderivative of that
isnt the antiderivative the exact same numbers we get from the beginning
?
'the numbers we get from the beginning' being what?
if you're talking about the distance between x=1 and x=9 then no
because if our function curves, we cover more distance than just 8
the shortest distance would be a straight line, which our function clearly is not
@bronze phoenix Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Anyone good at Taylor series?
Translation is at the bottom of the image. I was struggling to approach this, because I sort of assumed that the answer would be 0 due to the fact that x0 is 0, and that would be substituted into the x inside the function.... right?
In this type of question, I would be using this:
do you really want to compute 17 derivatives of that thing
because we are looking for an index of 17, I started by approaching (x-a)^n first. I replaced a with 0 so it's just x, and I replaced x with the contents inside the ln(x), so --
exactly, I did not want to suffer
yeah just use the series for ln(1-x) or whatever
because I assumed that the derivative would just continue to equal 0
ohe
this thing?
yeah
and instead of x you have -x^2 here
& don't forget multiplying by x the whole thing afterwards
and the n... I would be able to find n through the use of the (1-x^2)^n * x from earlier.
becomign -x^{2n+1}, and 2n+1=17, n = 8...
yeah n=8
Is the answer (-)x^16 / 8? :3
that should be it
well - x^17 /8
but the constant in front is correct
@floral terrace
@floral terrace Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Yeah I realized that later, thank you anyway :3
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
how can I find the domain of this equation?
Is it x^2 + 1 or (x^2 + 1)?
log(x^2) +1
well, what can you conclude about the domain of x when you have log_10(x^2)
R ?
cuz x^2 > 0 for all real numbers
well can x be zero?
no
so x!=0 is the domain?
because when I write it in geogebra it doesn't show the answers -1 and -10
only 10 and 1
<@&286206848099549185>
for $x = -1$ you get $(-1)^{\log_{10}(2)}$ though
WhereWolf(ping if needed)
oh
yes -1 and -10 are indeed solutions
geogebra probably missed it as the function is not continuous for x<0
@misty venture Has your question been resolved?
ok ty
.close
Closed by @misty venture
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Need a bit of help on this question
I’ve taken the area of A_1 to be a^2
And since the progression is geometric, the area of A_3 = (ar)^2 (where r is the common ratio)
So far all I’ve got is the equation (ar)^2 = a^2 + 1000
I have no clue what to do with it or how to solve for a and r
I’ve also got r = sqrt(1 + 1000/a^2) but that is derived from the above eqn so idk what to do
Any help will be greatly appreciated
@spring tide Has your question been resolved?
<@&286206848099549185>
?
Need some help on how to solve this question
which
Here
Not for school, it is for a competition but we’re allowed to ask for help as long as we can show our work
ALRIGHT
@spring tide Has your question been resolved?
.close
Closed by @spring tide
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Can’t understand how to fully solve this
Closed by @supple flume
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
hello, i am absolutely lost on laplace transforms
this is a question from a practice test
i've tried looking at videos for laplace transforms and information from the internet
but everything looks different
I'm also provided with 4 multiple choice answers but i dont understand how to get to those
my teacher has provided 0 learning material online so im kinda clueless rn
@halcyon zephyr Has your question been resolved?
i totally understand people avoid this stuff, I tried to do that too 

Hello, do you know how to get the laplace transform of a derivative?
im using a transfer table
A laplace transform table I guess (?
yes
It should have information about Laplace transform of df/dt and d²f/dt²
yes df/dt = 𝑠𝑌(𝑠) − 𝑦(0)
and d²f/dt² = 𝑠²𝑌(𝑠) − 𝑠𝑦(0) − 𝑦′(0)
am i supposed to transform both sides of the differential equation?
Yes
Laplace transforms are a useful tool for solving differential equations
They "convert" those equations into "polynomials"
So you can solve for Y(s), or R(s)
In this case, they want you to isolate Y(s)/R(s)
Given y is the physical system's output, and r is the input, the transfer function is defined as Y(s)/R(s)
yeah that makes sense
Remember that initial conditions are 0, that simplifies it a lot as y(0)=0 and y'(0)=0
currently i have the left side of the equation, but im not sure how to continue writing
how does the text to math work, lemme give it a shot
$R(s) = M(s^2y(s)-sy(0)-y'(0))$
♡ Mustard ♡
amazing
but then for the right side it would be $R(s) = -b(sy(s)-y(0)+k(r(t)-y(t))$?
oopsie
$R(s) = -b(sy(s)-y(0)+k(r(t)-y(t))$
♡ Mustard ♡
i feel like im forgetting something
Why are both equal to R(s)?
I dont know, I thought I'd get Y(s) by solving R(s)
im assuming R(s) is coming from the laplace transform
Start from this equation. Take the laplace transform of both sides of the eq
It's like when you have an eq. and take the derivative on both sides
okay
$\mathcal L\left{M\dv[2]{y}{t}\right} = \mathcal L\left{-b\dv{y}{t}+k(r(t)-y(t))\right}$
ELeonardo
♡ Mustard ♡

What's rt and yt?
The laplace transform of some function f is usually written as (capital) F: F(s)
well r(t) should be the input and y(t) the output
im not sure what the outcome should be after the transform
if all initial conditions are 0 then should rt and yt also be 0
at least im assuming that it means 0(t) so 0
i feel like younger me learning math for the first time like 12 years ago 
But you're taking the laplace transform, not evaluating them at 0
I mean rn you're doing
$\mathcal L\left{M\dv[2]{y}{t}\right} = \mathcal L\left{-b\dv{y}{t}\right}+k(r(t)-y(t))$
ELeonardo
Instead of
$\mathcal L\left{M\dv[2]{y}{t}\right} = \mathcal L\left{-b\dv{y}{t}+k(r(t)-y(t))\right}$
ELeonardo
oh yes
so k(rt-yt) is not the correct transform of k(r(t)-y(t))
theres nothing that looks similar in my table 
they are just functions
for example, laplace transform of r(t) is R(s)
.
is that something like this? or do i understand wrong
No, that's the laplace transform of an impulse function
you don't know what r(t) or y(t) are, so just write their transforms as R(s) and Y(s)
yes
so that means I have R(s) and Y(s) and now I have to solve it so i get Y(s)/R(s) on the left side of the equation
yes
oh that makes sense now yeah
ELeonardo
amazing, i'm gonna simplify and solve if i can
♡ Mustard ♡
Ok
For future problems, if the statement says that initial conditions are 0, then you can use this as the remaining terms cancel
$\mathcal L\left{\dv[n]{f}{t}\right} = s^n F(s)$
ELeonardo
I think this the right answer
i am left with 2ks and one b
and s^2
I was wrong 
oh well
Where did that come from?
Wouldn't it be s^2 + bs/M + k/M?
Probably came from me doing something wrong. Ill check after dinner :)
Send your work if you can
@halcyon zephyr Has your question been resolved?
working on it :)
What is the answer?
I can help in a bit, I need to do something
♡ Mustard ♡
.close
Closed by @halcyon zephyr
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
You might wanna try #foundations
Closed by @high harbor
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
hiya, I'm currently working on part B but I don't really understand why the answer for x from cosine has 2 values, 39.2 and 140.8. I got 39.2 from cos^-1(1/5) but I can't find 140.8. Thank you so much.
this is the graph i drew
@dusk remnant Has your question been resolved?
Hello, try drawing the angle cos^-1(1/5) in the unit circle
That angle is 2x, also remember that 0≤2x≤360 according to the statement. Is there another angle in the unit circle that has the same cosine?
@dusk remnant Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
i need to find the standard deviation in a dataset of 17, 22, 22, 30 (answer rounded 2 decimal places)
<@&286206848099549185>
hey
i need to find the standard deviation
no
alright
you know what the mean/average is ?
we'll use that to get the standard deviation
the mean is 22.75
,calc (17 + 22 + 22 + 30)/4
Result:
22.75
no i dont know
okey
so the idea of standard deviation is that it's number that measures deviation from the average
it takes a few steps to compute
i got 5.75 and -7.25
for ?
22.75 minus the extremes
could you compute value - 22.75 for each value of the dataset, not just the extremes ?
-5.75, -0.75, -0.75, 7.25
okey
now could you square each one of them, then take the average of the values you get ?
(the square helps us count the positive and the negative deviations equally)
the squares are -33.0625, -0.5625, -0.5625 and 52.5625
i'm putting what the calculator told me
is it the same answer as before just without the negative sign?
yeah pretty much
33.0625, 0.5625, 0.5625 and 52.5625
ok yeah
now take the average of those
we're averaging all the deviations in the dataset now
21.6875
ok
now that's a number called the variance of the dataset
take the square root of this, and you'll have the standard deviation
ah crap they wanted the sample standard deviation
sum all those and divide by 3 instead of 4 then
and then square root again
is it because there's a mode that i divide only by 3?
nah it's because we're working with a small sample, this formula works better
(but it's quite theoretical to know where the n-1 comes from instead of n)
i got 5.38
aight did it work ?
yeah you typo'd there
the last three should be 1 1 1
for some reason i read it as 22
aight
yeah but remember, we want to divide by 6-1 = 5, not 6
I just wasn't sure which formula you used at the beginning
yes
yeah you're just doing each step individually now
well we already computed deviations from the mean twice in this convo
I guess you can fill it out yourself
is it each data item minus 108?
yeah
.close
Closed by @magic fox
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
,rotate 270
thats for first bullet point
yea i understand how to read then
but
like
which means that visually speaking, f(x) will be in the gray area here for x>3
i duno how u apply
yea
but like thise two bullet points
dont restrict
anything?
like
i dont get it
they do restrict it
bullet 1: gives us the blue points
bullet 2: gives us the green point
bullet 3: gives us the orange region
bullet 4: gives us the purple region
so
because of the orange region, f(-oo)>=0
and since f will be a polynomial, we will get f(-oo)=oo
and because of the purple region, f(oo)<=0
and since f will be a polynomial, we will get f(oo)=-oo
does that make sense?
and since you just have to draw it, it should be doable
we can actually also calculate the easiest possible polynomial that matches the problem
if you are interested in that
@formal pasture Has your question been resolved?
can we try
let's first talk about the degree of the polynomial
yes, good 👍
how can u explain
the degree tho
like lets say
the teacher asks
how u got it
how can i show it
do i say like three roots
no
we expect f(-oo)=oo and f(oo)=-oo
if we look at a polynomial in the infinities, then only the term with the highest power matters
so in our case if we have a degree of n, then f(oo)=a*x^n
if n is even, then f will be positive infinity on both ends
which is not the case here
its odd
yes
etc
then we notice that we have at least 2 roots
yes
there is a theorem that states that a polynomial of degree n can have at most n roots
yes
so our polynomial with at least 2 roots must be at least of degree 2
and n-1 turning points
but since it has to be odd, it must be at least 3
yesokk
then we just look at the easiest possibility
we say the degree must be at least 3
what we now try to argue is that a polynomial of degree 3 can actually be valid here
that being said, polynomials of degree 5, 7, etc. will also work
yea
but they make it more difficult
yes
and odd
yea
the thing is that we only need 1 turning point here
ouesyes
you can see that in the graph you sketched
yea
is n-1
are those where the derivative changes right?
or was it where the second derivative changes
ahhh ok
and vise versa
yup
yea i think i got it
this was ely helpful
and a polynomial of degree 3 satisfies that
now for the actual equation:
we use the fundamental theorem of algebra
we assume that we do have 3 roots
yes
this is similar to the graph we have
but on the left we have 2 roots
so we move them closer to arrive at the graph you had sketched
what does this mean?
it means that the root on the left is a double root
no
the left
is single
it goes theough the axis
it skims through it
double bounces off axis
in my sketch
its double
yes
yes
mb
like this
i thiught we r talking abt urs
yess
that root on the left is x=-1
the root on the right is x=3
assuming that a,b,c are our roots, then:
f(x)=d*(x-a)(x-b)(x-c)
that is a theorem we can use
which i can't prove for you here
yea
if you are interested in why that works, look up fundamental theorem of linear algebra
we have the roots x=-1, x=-1, x=3
so we get:
f(x)=d*(x+1)^2(x-3)
now we can use the other points to get d
f(-3)=d(-2)^2(-6)=-24a=16=>a=-16/24=-2/3
with the other point:
f(0)=d(1)^2(-3)=-3d=2=>d=-2/3
one of those would have been enough
but good that t hey match
yes
so now we can put it together
f(x)=-2/3 (x+1)^2(x-3)
and if we visualize it, it actually works
🪄
yessss
if we were to solve for degree of 5 or more, we would have more unknowns which we could not solve for
we would instead get a set of solutions
Closed by @formal pasture
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
help
,tex .exp rules
riemann
so it would be (p/r)^c?
right
Closed by @barren karma
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
could someone explain this to me
@mossy pivot Has your question been resolved?
Owner: mniip (207092805644845057)
Icon: Icon Link
Verification: High | Must be a member for more than 10 minutes
2FA: Enabled
Roles: 70
Members: 176624 humans, 8 bots | 176632 total
Channels: 151 text, 10 voice, 16 categories, 1 stage, 5 forum | 183 total
Server Boosts: Level 3 | 82 boosts total
Created at: <t:1484176940:F>
A brief description and guide on how to use me was sent to your DMs!
Please use ,list to see a list of all my commands, and ,help cmd to get detailed help on a command!
@mossy pivot
Sin is positive, Cos is negative
sin (y) cos (x)
It's in Quadrant II (where degrees 150, 135, 120 are located)
Yes. I'd suggest remembering the unit circle (not hard memory, figure it out): I'll give you my method of figuring it out in a moment here.
i think i kinda got it down its kinda the same but flips in quadrant 3 and 4
Okey dokes! Remember, in Quadrant 4 the numbers are 5, 7, 11
goes out of the usual pattern.
sure
how do i turn the degrees into radians do i multiply by 180/pi
Degrees > Radian Degree * (pi/180)
Radian > Degree Radian * (180/pi)
16/65^2 = 256/4225
do i replace 16/65 in the equation?
thenn you subtract the value from both sides adding 1. Square root the value and then you get your answer.
Into Sinx, yes.
But it shows that you must square its value
Look at this:
(uploading work here, one second)
sin^2(x) can also be stated as [sin(x)]^2, thus sin(x) = 16/65 which (16/65)^2
No. Sin(x) = 16/65 in other words, sin(x) is 16/65
Yup. Square the numerator and denominator.
how do i get rid of the 1
1-(255/4225) = 4225/4225 - (255/4225)
when you add or subtract, you must get like bases so multiple the denominator and numerator of 1 by 4225
im a lil confused now
how come?
how did u get 4225/4225
oh ok. Look at this:
same thing for subtracting
We want like bases, in other words, same denomintaor.
damn my ass cant add fractions lol
Ok. Understood. You may not have done it in awhile. Don't worry about it.
1 is 1/1 so you multiply both the denominator and the numerator by 4225
you want to get rid of it, so when it's 4225/4225 you do not simplify it to 1, just subtracting 256/4225
1/1 * 4225/4225 = (4225/4225) - (256/4225)
I'll write it in latex so it's easier to read if I could remember how to work it
$\frac{1}{1} * \frac{4225}{4225} = \frac{4225}{4225} - \frac{256}{4225}$
there we go
Tank_Driver011
oh ok
🥲
and then 4225-256 sqrt that get 63
its sum decimal but
nearest whole number ig
and sqrt 4225
65
and cuz cos is negative in quadrant 2
thats why its -63/65
Yup!
alright thanks i have something else im struggling on but i wanna watch the video first
Great! I have to leave, as it's getting late on my end but if you need more help, feel free to ping helper
Closed by @mossy pivot
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Whats the power set for A = { {}, {a,b}}?
Is it P(A) = { {}, {{a}}, {{b}}, {{a,b}}}
You only want the subsets of A. {a} is not in A, so {{a}} should not appear in P(A).
might help to substitute the current elements of A with some letter, then take the powerset, and substitue back
@vast drum Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Prove that $||u+v||^2 = (u+v) \cdot (u+v)$
Derivative
no idea how to do this
like i could say that it equals to $||u+v|| \cdot ||u+v||$
but how do i interchange magnitude and direction
to assume that it is the dot product, it needs to be same direction
Derivative
for me to remove to make u + v a vector and not a norm, I need to make sure that the norm is in the same direction as the vector right
i know that the norm or length of v is $\sqrt{v_1^2 + v_2^2 + ....}$
Derivative
depending on R
so the norm of u+v vector is
$\sqrt{(u_1 + v_1)^2 + (u_2 + v_2)^2 + .....}$
Derivative
Derivative
Try expanding the right side using the properties of the dot product
Or you can try expanding these squared terms you've generated from the left side
ok so here is what i see
$u_1^2 + 2u_1v_1 + v_1^2 + u_2^2 + 2u_2v_2 + v_2^2 + ....$
Derivative
now if i combine the u_1 ^2 together and v_1^2 together
i get
$||u||^2 + ||v|||^2 + 2(u\cdot v)$
Derivative
There, almost done
Derivative
seems like its factorable
yep
Derivative
but i don't know why
Xenophon
and so on
Derivative
ahhhhhh
Yeah
dot product is associative
and mag squared is dot product of a vector with itself
but $u\cdot u= ||u||^2$ !!!!!
Derivative
great
Derivative
well thank you very, very much @shut river for your help
Closed by @zenith vector
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Could someone help me graph this with the requirements - I know I messed up somewhere but idk where
@heady granite Has your question been resolved?
<@&286206848099549185>
Is it an odd function? It doesnt go through the origin
Odd functions have rotational symmetry around the origin, not reflective symmetry across y=x.
This is an odd function for example
@heady granite Has your question been resolved?
Closed by @heady granite
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
I'm a bit lost on the step where it says (product rule), what acctually happens here?
why can the term $3x2ex**3y be ignored?
okey I will do
ah and these first order ODE's are always like a product of eachother?
.close
Closed by @fathom raft
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hi need some help with some discrete math: Prove the following statement:
Let A, B, C and D be sets. If B ̸= ∅ and C ⊆ B and A × B ⊆ C × D, then A ⊆ D.
Currently have something like this: suppose B ̸= ∅ and C ⊆ B and A × B ⊆ C × D, then A ⊆ D.
firstly, since B ̸= ∅, there exists an arbitrary element b such that b ∈ B. Let a be an arbitrary element such that a ∈ A. Since A × B ⊆ C × D, this must mean that (a,b) ∈ CxD. If (a,b) ∈ CxD, there must exist some arbitrary element c such that c ∈ C and an arbitrary element d such that d ∈ D where (a,b)=(c,d) because (a,b) ∈ CxD. This implies that a=c and b=d.
You've gone off the deep end. There exists some element c and d, such that a = c and b = d,
but if c and d are arbitrary, then it's not necessary that a = c, b = d
Or, okay I think that's what you're saying
My brain has been getting cooked I need help walking through the problem if that makes sense 😅
Don't use the word "arbitrary" since c and d are actually specific
The big find is to notice that A is a subset of C, and B is a subset of D
Both are implied from A×B being a subset of C×D
How do I get to this assumption
The Cartesian product one?
C ⊆ B is given...
I just want to make sure that a ⊆ C and b ⊆ D because of the (a,b) ∈ CxD
Let a ∈ A, b ∈ B. So (a,b) ∈ A×B.
That implies (a,b) ∈ C×D, or that a ∈ C, b ∈ D.
In other words, A ⊆ C, B ⊆ D.
And because we're given C ⊆ B, we get this: A ⊆ C ⊆ B ⊆ D which is A ⊆ D
Correct?
I'm assuming that is the case
<@&286206848099549185>
@upper abyss Just want to confirm, will close after 😛
yes
Closed by @wise hedge
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hello, I have a simple problem. It states "Tony has 830 bottles. A small bottle is worth 10 cents and a bigger one is worth 40. If Tony got $159.50, how many of small and bigger bottles did he have?" I were able to solve it using two equations:
x + y = 830
0,1x + 0,4y = 195,50
However the question implies that it should be done in one equation and we haven't necessarily been teached ways with multiple equations. I can't think of a one equation answer. Does it exist? The answer was 575 small and 255 big.
you can skip straight to one variable
small bottles is x, and you use (830−x) for large bottles
Sorry, how could I combine the two equations with this info?
i don't understand what you mean
The question was that is it possible to solve this using only one equation instead of two
the first equation doesn't appear, you only have the second equation, without y
it's exactly like you just don't show any initial steps
and write the combined equation from the start
but that's what they must have meant
I still don't get how I could combine them
okay ping helpers
I don't know k ow if this is old enough
i guess not
Ig this is not that critical, I don't even have ro solve this, just wondering if I could with one equation
if you solved it, you must have had one equation at some point
i don;t understand how you solved it otherwise could you show it?
It's in the post, using two equations
.
there's no solution
In the end there is
what
Look at the very end
that's the answer
Yes
you;re saying you gave the equations to the computer or something?
No
I solved it using them two
so at some point you had one equation, that's how it works as far as i know
it would be natural to straight up write that equation as the first step, then you have one equation
it's like, the first equation only appears because you made 2 variables, if you start with only x, that stands for number of small bottles, or number of large bottles, you still can get an equation
@rotund wind Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
For Question 2 B, I am unsure if I overcomplicated it or if i’m doing it correctly
You got it right
They just asked you to complete the square, right?
yep
i dont think so
Seems like that's what you did, and you got it correct. So what's the problem?
Oh I see what they're asking
y = 3 - x^2 - 8x
Complete the square from here
Don't plug in y = 0
if i factor out the negative sign, does y also become negative
so it becomes x^2 + 8x -3 = -y
alrlr
@vernal kite Has your question been resolved?
so how would you find the maximum/minimum vaule of that
max min value of x?
none
you found the function in terms of x
if you want to find max or min you have to find the turning point because it a parabola
so that means i have to solve for y then?
u find x, sub the x values in and then find y
ye
but isn’t it just question 2 a?
yep
you had it right up untill you sqrted everything
you dont need to solve for x,
you need to put it in the form a(x-h)^2+k
ohhhhh
so you just had to minus 19 from both sides
so once it's in the form, what do i do then
if its in the form a(x-h)^2+k then the turning point is at (h,k)
so the equation 3(x-2)+5 would have the turning point (2,5)
ohhhhh
wait i remember this
it's been a long time since i've learn this so i forgot everything
thank u :)
np
wait but if the form has -h and +k and this has +4 and -19, then what
do i just switch the signs around?
so its -4 and -19?
yea
wait so are u correct or is the answer correct
the answer is correct
Closed by @vernal kite
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
how do i convert this to m/sec
from m^2/sec
why would you?
.close
Closed by @dreamy zenith
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
need help on question 1, 2, and 5
For 1 you can use difference of squares
@tawny drum Has your question been resolved?
For 2, you can combine the last 2 restrictions to form a relation between the number of red and white balls, then use number theory
and some bounding
can you explain what bounding is??
its like monthly questions
