#help-38
1 messages · Page 2 of 1
Does it make sense how we just plugged G(x) into F?
I’m going to ignore f(x) to start with if that’s possible
So..
g(x) = x+1
f(g(x)) = f(x+1)
All I’ve really done is add f function to the beginning of the g function now right?
(x+1)^2
Hmmm
well, that's just because x+1 is more than one symbol
f(x) = x^2
f(4) = 4^2
f(a) = a^2
f(b+c) = (b+c)^2
f(x+1) = (x+1)^2
f(4t) = (4t)^2
a variety of examples
Some require parentheses because they're more than one symbol
Yeah.. I’m thinking of this like declaring variables as code and I think it’s kinda confusing me. I’m used to seeing the variable name when I call it but in math it’s replaced by a real value and I need to try and remember where that variable was
in math it can be replaced by anything lol
yeah the notation is different than programming
If that makes sense.. math doesn’t seem to have the liberty of colour coded IDE like VSCode.. or if it does I need to download it 🙂
You can download different colored pens lol
Haha
I do wonder though if there is a program that will do this? It would be like VSCode but for mathematicians
Typing is more challenging on keyboards.. I’m using GoodNotes on iPad and seems to be pretty decent for math
Anyways I do hear what you are saying..
Let me think this over
With these
f(x) = x^2
f(4) = 4^2
f(a) = a^2
f(b+c) = (b+c)^2
f(x+1) = (x+1)^2
f(4t) = (4t)^2
Technically this
With these examples are you overwriting the old function f(x) at the very top?
Should the following ones be g,h,I,j,k, etc?
Or you are showing exactly what f(x) at the very top can do to literally anything you plug in
I see I see
I get it now
It's the same function with different things plugged in
So FoG
Like f(2) means plug 2 into the function f(x)
Same idea as f(3)
But if you change the letter to g(x), that means plug 2 into the function of g(x), which is a new function
f(x) = 3
g(x) = (x + 5)
f(g(x)) = …
I'm not sure what this means?
{3} to show it’s from f(x) = 3
As mentioned, f(x) = 3 is a constant function, mean it does not change with x, it's constant
So there's not a solution to f(g(x))
Oh
If it was f(x) = 3x, that's different
If f(x) = 3, then f(anything) = 3
It's a constant function
f(g(x)) = 3 for any x
if f(x) = 3
(where g(x) is defined)
yes
@lone mauve Has your question been resolved?
I think maybe you got mixed up between f(g(x)) and g(f(x))
@lone mauve What even is the question you have still?
If we take f(x) = 3 and g(x) = x+5, then
f(g(x)) = f(x+5) = 3
and
g(f(x)) = g(3) = 3+5 = 8
@lone mauve Has your question been resolved?
Closed by @lone mauve
Use .reopen if this was a mistake.
.reopen
✅
If we take f(x) = 3 and g(x) = x+5, then
f(g(x)) = f(x+5) = 3
and
g(f(x)) = g(3) = 3+5 = 8
This explains it perfectly! Thank you @inland orbit
I finally understand now
It’s like using variables in programming
Calling a function with a variable
function(var){}
they are literally just what they equal
I was over complicating things
You shouldn't compare things to programming like that. Yes, CS and math are similar but they are also different so you won't be able to find a perfect analogy that makes sense
Actually in this case I think it’s a perfect analogy. But instead of calling a var inside of a function it’s calling a function inside of a function.
Yes, it is like calling a function in a function, that's a good way to think of it
But also @night zodiac is right. You won't always be able to find a clean analogy between mathematical ideas and programming
But in this case, yes, it is quite a nice analogy
Well, I would agree: that’s a better way of putting it. “Won’t always be able to”, rather than “shouldn’t compare” and “won’t be about to find”
It was suppose to say "won't be able"
Well
Analogies are always helpful in understanding
But programming and mathematics are not the same
This was my point
The analogies will break down at some point. You cannot count on them. You may use the analogies to guide you but you should try to understand the mathematical logic as it is
Yes, I agree with you
@lone mauve Has your question been resolved?
Closed by @lone mauve
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.
$\cos(\pi-x)=-\cos{x}$
QuantumBee
For any acute angle x, pi-x lies in the second quadrant
Oh ok, ASTC?
I understand it now. Thanks mate🥰
you can also check with $$\cos(a-b)=\cos{a}\cos{b}+\sin{a}\sin{b}$$
QuantumBee
Closed by @cloud canopy
Use .reopen if this was a mistake.
nice username :)
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 flip a weighted coin that comes up Heads 40% of the time and Tails 60%. If you flip this coin 5 times, what is the probability that you see at least 3 Tails, rounded to the nearest percent?
anyone wanna help me?
would it be this (5c3) + (5c4) + (5c5) / 2^5?
if this was a fair coin it would be .5 right?
why /2^5?
thats the total number of flips
but getting heads has a different probability to getting tails
so its not just simple counting thing anymore
@frail current Has your question been resolved?
I said assuming we’re talking about a fair coin in this case
well in that case its fine
but you already have the answer dont you
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.
"Given directed line segment RT below, find the coordinates of such that the ratio of RS to ST is 5:1. Plot point S"
R=(7,-1)
T=(-5,-5)
8th Grade geometry class, my grade is already an 80, begging for help to learn 😭
@onyx dock Has your question been resolved?
@onyx dock 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.
any hints?
from rank nullity, i see that i need a list of n^2-1 elements
and eij where i/=j comprises of n^2-n elements which can be in the basis
so gotta find independent list of length n-1
with only diagonal entries ofc
i can find floor(n/2) more, if we take (e11-e22),(e33-e44)....
floor(n/3) if we do something similar like (e11+e22-2*e33)...
seems like i can do it so on, floor(n/4), floor(n/5)...
<@&286206848099549185>
ping me if anyone answers
nvm, if this was true rank nullity would get violated
@wraith hinge 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.
@latent pelican Has your question been resolved?
@latent pelican Has your question been resolved?
.close
Closed by @latent pelican
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.
hey all, having a bit of trouble with #9 here, I'm fairly certain I have to use substitution or elimination but I'm not really sure how to get that started
oh and the question is, use the definition of continuity to find the values of k and/or m that will make the function continuous everywhere
actually i believe i figured it out ill try and come back to see if im right
.close
Closed by @primal musk
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.
From this equation I need vo in terms of g and D but I can't do it
I'm getting here but I can't solve further
@rough hinge Has your question been resolved?
<@&286206848099549185>
@rough hinge Has your question been resolved?
.close
Closed by @rough hinge
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. The numbers a and b satisfy the equation 56a = 65b. Prove thata+ b is composite. Is this reasoning incorrect: a=65b/56 composite numbers is a concept defined only for natural numbers so a+b is a natural number, therefore b+65b/56=121b/56 ∈ N therefore 56 l a+b
<@&286206848099549185> plz help lol thx im an idiot
@tidal igloo 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.
r^4 - 6r^3 -89 r^2 -294r+2401 = 0
I already tried with rational root theorem
and neither +- 1, 7, 49, 343, 2401(divisors of 2401) give 0 in the final one
I want to clarify I already know the result I just have to do it by hand.
@quiet remnant Has your question been resolved?
<@&286206848099549185>
,w r^4 - 6r^3 - 89r^2 - 294r+2401=0
@quiet remnant Has your question been resolved?
@quiet remnant Has your question been resolved?
Lol
root finding method maybe but idk how youre gonna end up at these numbers
I already did it
Wdym
its not gonna get you an exact answer anyways
since the roots are so bad
hrm
that symmetry of the 17 one
I did it with synth division
But I didnt get the result
Which is 3.67 btw
Well there are two results 3.67 and 13.32
But yeah
well i guess its symmetry around 8.5
maybe you could guess
the solution takes the form (x-8.5-a)(x-8.5+a)(Bx^2 + Cx + D)
where the final quadratic is nonfactorable
youd have to inform this guess with something
you could do like
bisection or something idk
somehow or another youd end up that it looks like you have those two roots about the point
guess its 8.5
youll have to inform a guess some how
.close
Closed by @quiet remnant
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.
Isn't the inequality wrong here?
I'm getting x - 2 - (2/x+1) > 0
Am I wrong?
how did you get x-2-2/(x+1)?
I took the minus sign out from the LHS, reversing the inequality
I then brought the RHS Fraction term to the left.
The original question:
This is how I got my answer:
<@&286206848099549185>
@wraith hinge 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.
not sure how to do this. any help would be appreciated
Express 9 interma of 3
i understand that but im not too sure how to do that
It might be the wording tripping you up
I'll just say that 9 =3^2
It just wants 3^(something to do with x)
oh i see
ok that makes a lot of sense now
nvm i still dont know what to do from there
i understand this but dont know what to do next
Ok so
Imma write it a bit weird (9)^4x+6
9=3^2
(3^2)^4x+6
@smoky sundial
What happens when you raise a power to another power
do you just multiply them together?
so would it be 3^8x+12?
Yep
Closed by @smoky sundial
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.
Guys is making this type of statement valid?
Not that the statement is true but sure that is still a statement nonetheless
No
yeah, i realized that after i posted it
Wait hold up how’s that false

Also the first statement, i feel its true 
@stark bison enlighten me
Umm wait
Pick x and y at random then plug them in. See where that gets you
@humble yew Has your question been resolved?
No
why not?
Think about x=4680 y=1
x,y = 0 is a counterexample
4680 can be written as 4680/1
,w 4680/(4680^2 +1^1)
4680/0 is not
Yes
this looks very rational
Yees my b
but any value in Q is of the form p/q where p and q are integers
0 is also considered an integer
so x and y would have to be in the set of natural numbers for the statement to be true
@humble yew 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.
So I have a function $f:(X,d)\to(Y,\rho)$ between two metric spaces with $a\in X$ a limit point of $X$. I define the set $A_a(f)\subseteq Y$ by $b\in A_a(f)$ iff there exists a sequence ${x_n}\subseteq X\setminus{a}$ such that $x_n$ converges to $a$ and $f(x_n)$ converges to $b$. Suppose $A_a(f)={f(a)}$. I am trying to show that $f$ is continuous at $a$. I have shown that for any ${x_n}\subseteq X\setminus{a}$ such that $x_n$ converges to $a$, if $f(x_n)$ converges in $Y$ then it converges to $f(a)$. I have not been able to show that $f(x_n)$ converges in general though.
Beous
@vast flint Has your question been resolved?
@vast flint Has your question been resolved?
@vast flint Has your question been resolved?
.close
Closed by @vast flint
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 studying discrete mathemathics and I am preparing myself for an exam, I am stuck on the set notations (Union, Intersection etc.) I have a question what does the bar above the variable means?
can you show it in context
Yes, is ok If I post a pic of the HW?
sure
so its most likely the complement of C
Can you give me an example please?
indeed
``.close`
.close
Closed by @neat knoll
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.
Wdym
Closed due to the original message being deleted
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 help with b ive done work for 9. a)
@wraith hinge Has your question been resolved?
Closed by @glacial garden
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.
This is embarrassing, but someone please help me
Try factoring by grouping
Aka, for the cubic, factor the first two terms and second two terms separately and see if it can be factored further from there
Should I use synthetic division?
Sorry, I didn't understand this
Try factoring x³ - 3x² and factoring x - 3 (which can't be factored anyways)
Why (x - 3)²?
Then why didn't you get x⁴ when factoring the first time?
Yes
And don't forget the original x that was there
And now it's factored as much as possible, at least in the reals
Hey can someone help me with question b
No
Oh okay
x(x^2 + 1)(x - 3) = 0
Yep
So x equals to 0, 1i, -1i, 3?
Remember the problem asks for real solutions
They asked for real roots right
Closed by @molten comet
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.
id apply rational roots test at the start after setting it = 0 to get (2x-1)(3x^2-x+1)=0 first
its the results of factoring this with rational roots test
so what does that mean then?
@proven bobcat 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.
Not sure if I’m doing these right, #4 and 7 are especially confusing for me
what is the question for 4
Decide whether or not there is enough information ti determine if p is parallel to q
If so state the theorem you would use
what
look at it sideways
lol
@short helm 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.
f(x) is 1/x btw
f(x + h) = 1/(x + h)
Closed by @sly spoke
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 trying to write up some tensor equations where the indicies, and the number of indicies are both arbitrary
Example a $\sum$ that can go over any set of indicies
FargothUrIsOnline
Is it proper to write something like $\sum_{i_1, \text{ ... }, i_n}$ to represent how generic I'm being
FargothUrIsOnline
so I'm writing i_1, ..., i_n here but is there some general symbol I can use to represent a set of arbitrary indicies?
@clear zodiac 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 have drawn z < 5 but forgot how to do z< z-6i
surely like the z<z-6i line would be above the z<5 circle
|z-point| is the distance to a point in the complex plane
so |z| is distance from (0,0) and |z-6i| is distance from (0,6)
and you have to figure out what it means to be closer to (0,0) than (0,6)
so would the line be above the circle?
yup
yea inside the circle and below the line
Closed by @acoustic bay
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.
Closed by @supple furnace
Use .reopen if this was a mistake.
.close
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.
The OP arm rotation is
controlled by slotted guide A
that slides horizontally
as the picture shows. If the
speed with which A moves to the
right is 1.2 [m/s] and with a
acceleration of 9 [m/s2], determine
the angular velocity of the OP arm
when x = 50 [mm]
@lofty charm Has your question been resolved?
!close
Closed by @lofty charm
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 with this please
What is exactly the problem?
Bruh don't give away answers
That's it? I thought it'd be more complicated
@shut edge What made you think it was more complicated? Have you done any attempts?
actually I think you drew wrong
Is the drawing in the problem itself or a product of your attempt to solve it?
I have and came to the conclusion the entire C circle could be the answer
Before I posted the problem here
I didn't alter the arrangement of the circles
They're separate like that
Ok, start by drawing the intersection of A and C, then the intersection of B and C, then see what their union looks like
Haha, now I understand
read this article it will be more easy for you good luck dude
Then I had another confusion. Same figure, but the question this time is (A ∩ B) ∩ C
Same thing, start by drawing A ∩ B
A ∩ B can't be drawn
Bro, don't give answers
As in?
I don't get what you meant by overlapping
Unless you are told otherwise, you can't assume that A and B don't share elements
Ah, no. The figure isn't like that
It's the same figure as this
A and B don't overlap
Ok, if you are supposed to work with the one you have, then that's good, A and B don't share elements, so their intersection is empty
But C overlap A and B
Whew
Then I have one last question. It's A ∩ (B ∪ C). This time I'm assuming the answer is A ∩ C?
Oh, and the figure is the same as the last two times
Yes that's good
Closed by @shut edge
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.
Not sure this is the place to ask, but I have a small confusion about leapfrog method for numerical DE solving
this is the image im working from, with leapfrog on the bottom
I have code, which works, too
% [tvec,Uvec] = LeapfrogSys(f,tspan,U0,k)
% Leapfrog method
% Inputs
% f: name or function handle of the right-hand side function f:(t,u)->f(t,u)
% tspan(1),U0: initial condition (U0 can be s-vector)
% tspan(2): end time, so that number of steps N = (tspan(2)-tspan(1))/k
% k: stepsize
% Outputs
% tvec: vector of t values
% Uvec: vector (or matrix) of corresponding U values
U0 = U0(:); % make sure U0 is a column vector
s = length(U0); % number of equations in system
tvec = tspan(1) : k : tspan(2); % a row vector
N = length(tvec);
Uvec = zeros(s,N); % REMEMBER OFF BY 1 ISSUE
% FOR STARTING INDEX ON LOOP
% concerned about transpose here
% check :-swap anu eulersysec :)
Uvec(:,1) = U0;
% start up with one Euler step
fval = f(tvec(1), U0);
Uvec(:,2) = U0 + k*fval; % 0.5 from half-step needed
for idx = 2:(N-1) % this should be n-1 i think ...
curr = Uvec(:,idx);
fval = f(tvec(idx), curr);
back = Uvec(:,idx-1);
Uvec(:,idx+1) = back + 2*k*fval;
end
tvec = tvec'; % to match MATLAB output
Uvec = Uvec';```
what im confused about is the end of this, following "start up with one Euler step"
shouldnt some component of this method involve a half-step of time?
why are all the time inputs just pulled directly from an evenly spaced time array? ( tspan(1) : k : tspan(2) )
@viscid flower Has your question been resolved?
@viscid flower Has your question been resolved?
.close
Closed by @viscid flower
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.
what is a homogeneous equation?
separable equation is of the form dy/dx=M(x)N(y) but idk about homogeneous
In the context of differential equations.
If the differential equation
P(x, y)dx + Q(x, y)dy = 0
has homogeneous coefficients, i.e., P(x, y) and Q(x, y) are homogeneous functions of the same order then it can be shown that y = xv will transform the differential equation into a separable one*.
If a function f(x, y) is homogeneous of order n then
f(λx, λy) = λ^n f(x, y).
Depending on the book λ can be any number or just positive. For example, for x > 0, λ = 1/x >0 gives us
f(1, y/x) = f(y/x) = x^(-n) f(x, y) or x^n f(y/x) = f(x,y).
You may see a definition which uses this as a alternative definition of homogeneous.
If P(x,y) = x^n f(y/x) then it's homogeneous of order n.
*See page 57 of Ordinary Differential Equations by Morris Tenenbaum and Harry Pollard.
You could use google btw
Ooo okay i'll read that, thank you!
.close
Closed by @supple furnace
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 to solve this question without guessing functions?
Try to substitute 2 in f(x) in the limit and see whether you can factor something in the numerator
By that I mean to substitute f(x) with f(2)
@hollow steeple
Ping me if you need more help
@hollow steeple 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.
How do I proof, using induction, that $\sum_{i=1}^{k} \frac{1}{2^i}=1-\frac{1}{2^k}$
it's not true, take k=0, then the LHS is 1 but the RHS is 0
probably the sum should start at i=1
𝙹o
ok, i assume it's clear that it is true for k=1
Yes
now assume it holds for some general k, and the goal is to show that it holds for k+1
If you want write it on LaTex
to get started, try writing $\sum_{i=1}^{k+1}\frac{1}{2^i} = \frac{1}{2^{k+1}} + \sum_{i=1}^{k}\frac{1}{2^i}$
and then apply the induction hypothesis to the sum on the RHS
Bungo
So $1-\frac{1}{2^{k}}+\frac{1}{2^{k+1}}=1-\frac{1}{2^{k+1}}$
𝙹o
yes
And now we substract the $\frac{1}{2^{k+1}}$ term on both sides and get that indeed they're the same
𝙹o
Thanks man
sure
Closed by @sacred fern
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 should first start with the deepest parentheses if you know what I mean
In that case with (3²*2)
I got -75.2
show work
Yes please
@opaque bay Has your question been resolved?
Closed by @opaque bay
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.
any ideas how to solve this?
i mean, i know d is 4
other than that, i have no clue
What are the roots of this cubics? And how can you use them to form an equation.
-1 and 2
idk what to do with them, i mean i know it's also the points where the function changes its growth
Yeah and why are there only two roots when it’s a cubic?
i mean -1
idk exactly
You can clearly see two turning points
yes
Because one of them is a repeated root
Can you see which one?
Nope it’s -1
Because the curve touches the x-axis
And then just go up
So there are two roots there
-1 and -1
Well you technically have 3 roots
-1,-1 and 2
Can you form a factorised equation using these?
When you plug these values in your equation you must get 0
Like when you factorise a quadratic
$x^2 + 3x + 2 = (x+2)(x+1)$
Pure
This means -2 and -1 are the two roots
You can do the same thing for this cubic
Because you know the roots are -1,-1 and 2
ohh
well if i divide it by (x+1) since -1 is a root, i can multiply the quotient by (x+1)
to get the factorized equation
right?
You can factorise the cubic into three brackets of linear.
And you know the factors are (x+1)(x+1) and (x-2)
Because you know the roots of the cubic
@terse geyser Has your question been resolved?
Closed by @terse geyser
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.
Three cities A,B and C are located as shown in figure 3.33
City B is located 10 km east of city A, and city C is located 3 km north of city B. A new road is to be planned between A and C, as shown dotted on Figure 3.33. there is an existing road between A and B as shown with a solid line. If the road is built on the existing road between A and B, the cost will be 4 million *((USD)/(km))otherwise the cost will be 5 million *((USD)/(km)).
Find total cost?
oh
i need to decide where point P should be located, so that the cost of building the road is as cheap as possible.
Try parameterizing the cost by introducing some variable
pure :)))
Yeah I would try parameterizing this
For example you can find an expression for the cost in terms of AP
so x=4 mil/km and y=5mil/km
AP=AB-(PB)
Yeah, solve for PB though
a^2+b^2=c^2
In this case PC^2 = PB^2 + 3^2
Now plug in PB = 10 - AP
(10 - AP)^2+9=c^2
So PC = sqrt((10 - AP)^2 + 9)
yes
Now you can determine the price with AP and PC
Mxrcus
Yeah, so the cost is 4AP + 5PC (in millions)
Let's define the function to be f(x) = 4x + 5sqrt((10 - x)^2 + 9)
Now just find the min of this f
how do i know that?
Each kilometer from A to P costs 4 millions, so the total cost of the road from A to P is 4AP
Same thing with the road from P to C
why is it 4AP
Okay look if AP was 1km long, how much would the road cost?
i am sorry for being dumb❌ 
4 mil+PC
yes
yes
So whatever is the length of Ap
agree
Its cost will be 4AP
Can you now see why PC road costs 5PC?
idk what i was thinking
yes
Okay, so the total cost is 4AP + 5PC
Which is the same as 4AP + 5sqrt((10 - AP)^2 + 9)
✅
Now all we need to do is to find value of AP for which this is minimum
So basically find the minimum of the function f(x) = 4x + 5sqrt((10 - x)^2 + 9)
No, you should set the derivative equal to 0
Not the function itself
So first differentiate f(x)
how do i solve his
Differentiate 4x + 5sqrt((10 - x)^2 + 9)
what about the 5
mb
mb?
My bad
Are you having trouble with differentiating the sqrt?
yes
Use the fact that sqrt(x) = x^(1/2)
omg yes
sry
4 + 1/2(10 - x)^2 + 9)^-1/2
4 + 1/2(10 - x)^2 + 9)^-1/2
upsi
Don't forget about the 5 too
isnt 5 a constant?
It's a coefficient of the sqrt
Just like the fact that 4 was coefficient of x and thus didn't disappear
idk
i am lost
I GIVE UP
too dumb

thx for trying @stark bison
.colse
close
.close
Closed by @digital path
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.
<@&286206848099549185>
@valid glacier Has your question been resolved?
@valid glacier Has your question been resolved?
<@&286206848099549185>
dawg
you need to specify what specific ones you're having trouble with
let me see what you did
unless you're saying, that you typed in the exact values and still got marked wrong?
well the whole table, it doesnt tell me which ones are wrong
pretty much and used Vavg formula, plugged in values and still wrong
here is a better picture of a similar problem with the work
@valid glacier Has your question been resolved?
@valid glacier 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.
logic and proofs
can this rule also be p and q -> q?
or just p and q -> p
I'm looking at my professor's notes and he pulled q(a) from the simplification
instead of p(a)
upon inspecting. i believe that is a mistake and p(a) should be pulled for simplification
.close
Closed by @brittle 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.
I just need a clarification if this is right because im not sure
How many vertical stripes of fence are there?
6?
Count the drawing
7?
Ye
What about it
But the word problem says 6 strips i dont get it
But look at the drawing
You drew 7
7 vertical lines of fence
6 strips of fenced in field
@grave zenith 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.
Please don't occupy multiple help channels.
Closed due to the original message being deleted
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.
any help on 76?
,rccw
how is trigo ratio applicable in a non right angled triangle?
You can make right triangles from non right angled
can u elaborate?
I mean you can legit just draw right triangles inside the non right angled
but it asked about that trianfle
@vague walrus 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.
Can someone tell me which angle would be the one between the sum and difference of the vectors
what is the angle between them though
wait so lemme write something
How do i get to this
This was the answer but i dont understand how they said that was the angle
listen close
you will soon know
every door that has opened close one close soon know youll know what in the othert side
who i am fighting for
?
my guess would be to use the scalar product
since that defines angles
but we wont get arctan from that
so im confused
im gonna think a bit
he attached an image of this
oh wait
he got the right answer btw i just dont understand how he decided that angle
probably something with trianges but i cant figure it out
from this angle
the opposite would be |a-b|/2
the adjacent would be |a+b|/2
so we would get
tan(theta)=|a-b|/|a+b|
🙂
your welcome
have a good night :)
u2
.close
Closed by @silent kiln
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 anyone help me with this, this is not for a graade or anything learn what my sister is learning
X=4 y=2
Pretty much the asymptote is where the curve doesn’t hit
So x approaches 4 as y approaches infinity
Y approaches 2 as x approaches -infinity
?
Intake is wrong, this function has 1 asymptote, not 2
thats what got me confused
An asymptote is when a line gets closer and closer to some value but never quite gets there
a line
the line is the value and then the asymptote would be a number on the x or y axis?
So in your specific case the asymptote is y = 2
which is graphed as a horizontal line 2 units above the x-axis
The asymptote is just an equation
on my phone screen it looked like 2 myb
Not a value on the axes
is that becuase the line gets close to 2 but not quite at two?
Yes
no worries
Specifically an equation describing a line
ahh i see
and would that lead to part b?
it says describe the end behavior of the graphed function
Not all asymptotes need to be lines
You can have curved asymptotes
?
They're not understanding
Don't worry about curved ones
your asymptote is represented by the blue dotted line
yes
the line is closest to 2 at the curve
y = 2
correct
i understand that part now, but part b of this question is what im looking at now
okay
intake, you need to explain the process of why you ask that specific question.
I thought that would just simplify it
Since we're talking about the asymptote we're interested in the side of the line having to do with said asymptote.
don't skip steps in an explanation, it only causes confusion in the future.
yea sorry intake i actually havent learned any of this, im just trying to learn ahead
Question B is asking what the asymptote tells us about the function
is it right to assume since we know the asymptote is 2 then the answer would start with f(x) ->2?
for the first part of B ofc
yes, because the asymptote is y=2 and f(x) just means y
then we need to describe the second part
nice and how would i go about that
well
do we have a reason to believe the graph will stop going further to the right?
correct
as far as we know x can in theory go all the way to infinity
so the answer is going to have something to do with x -> infinty
so that would be positive infinity
in this case we know that f(x) approaches infinity as x gets larger because all of the answers provided say so
yes
the only question we needed to answer was how far would x go, and we came to the conclusion of infinity
so f(x)->2 as x->inf?
yea
and we have no reason to believe it will stop going to the left
so we start with f(x) -> 2 as x -> -infinity
true
and we have no reason to believe y will stop growing or that we would stop going to the right on the opposite side
answer would be a
yes
If you want I can come up with another question like it so we can verify your understanding
well i have a bunch of random questions from my sisters calculus reviews
Do you want another like this one to verify your understanding? (or maybe you happen to have one?)
different type of question
what type would this be?
this isn't an asymptote question, it's asking where the line breaks.
what does that mean
you see at x = -1 where it jumps up 1 unit without a connecting line?
no....
oh it jumps one unit from (-1, 2.5) to (-1, 3)
yea
but the function is discontinuous at x = -1 because the line isn't connected
so why does x = -1
ohh

Are you sure?