#help-28
1 messages · Page 154 of 1
yea
What is the measure of $\angle ADC$?
Dork9399
yea
what is the measure of $\angle ABC$?
Dork9399
57
What is the measure of CBD?
123
CBD, not CBE
uh
its an isosceles triangle with a vertex angle of 90
what does the make the other two angles?
The angles of the triangle are 90, x, and x. What does that make x?
45?
yes
so b=45?
So ABC = 57, CBD = 45. What does that make EBD?
78
So what is BDE?
12?
yay!
Closed by @sinful wasp
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 I cancel differentials ?
for example: if dx/dt = dy/dt does that mean that dy=dx?
uhhh... kinda
whats the context
idt that makes sense
because, dy/dx is its own thing,
But you can do that trick when doing integrals
no that'd mean the derivative of an arbitrary function is 1.
@charred geode 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.
hello
!15m
Please only use the <@&286206848099549185> ping once if your question has not been answered for 15 minutes. Please do not ping or DM individual users about your question.
Bruh
?
not really, but thats why im asking
<@&268886789983436800>
<@&268886789983436800> this can't be a doubt
bruh im just asking a damn question
Rules state u have to try first
Pls share what u have tried
I DID!
.
i just did a whole page of other work
i dont need to show you what I completed your not even a helper
<@&286206848099549185> its been 15 mins
Who need help?
i do
some guy interjected into my question
he was really rude
he was juding me for not understand a question
I am very sorry for him, if we understand everything it is impossible to learn
So what is your question?
kirito is a helper.
but for the question, if enlargement makes an image bigger, and reduction makes it smaller, then how do you think the small triangle b in question one must be scaled to make the big triangle A?
this is really disrespectful honestly.
.
so the first one would be enlargment and reduction is the 2nd one?
good, you got it
so basiclly englargment is bigger and smaller is reduction
yeah
Nice✅
That is
But u didn't share yr 2 page working
okay and I have one more question
.
yeah
yeah
its asking to find the scale factor out of these two
but im not sure how to find it
is it the bigger one?
To find the scaling factor, divide the lengths of the corresponding sides
For example in the figure on the right, the scaling factor is 2
The corresponding sides of the two similar figures
for each?
The larger figure is obtained by multiplying each side of the smaller figure by 2.
8/4=2
6/3=2
The scaling factor is the number by which you multiply the sides of one figure to obtain the other
you see how the figures are congruent? (they look the same, with the same ratios between side lengths)
I think factoring could help:
try factoring the side lengths on each figure ans see what factors match up
so would it be the 2nd one?
48/40
sso would the correct on be on the left?
@proven spade Has your question been resolved?
It looks like the question is asking for a number, not for you to choose a shape
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 graphed f(x) in desmos and the sign testing holds up when I check the sign from (1, inf) it’s always increasing and from (-inf,-1) it’s always decreasing.
But what if I have a function that changes concavity somewhere towards -inf and + inf? Will the sign testing still hold up
What question are you using the sign test for
well i dont have to use it here but i just wanted to try and see if i could curve sketch it
all i had to do was find the max or min points and find the stationary point
im just curious if i was to use the sign test to curve sketch
would the sign test catch whether there would be a change in concavity in a later interval
like for example i know that this function will always be concave up from (1,inf) but what if it changed somewhere during that interval ( ik it doesnt but just asking)
@twin wolf Has your question been resolved?
.close
Closed by @twin wolf
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.
Find the smallest possible integer n, such thar n! is divisble by 2⁵×3⁵×5⁷
Is the answer 35 correct?
My reasoning was since we need 2, 3 five times in the factorial and 5 seven times we can go with five and find the number with five seven times.
Or is 30 the answer?
Since there's two fives in 25?
@vapid spindle Has your question been resolved?
30 is correct
There are eight 5 in 35!
5
10
15
20
25
30
35
It’s excessive
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.
hi
if the 2 after square root of 5 is a power yes ur correct
oh shoot my bad i didnt see
i thought it was a power
so in that case
its just 2 square root 5?
its weird how its behind the square root lol why would not they just write 2*(square root of 5)
im guessing its a power
ye thats what i thought
ye possibly a mistake
is this correct
wait oops
u gotta show that 45 is equal to that not that 3 square root of 5 is equal to that
square root of 45= square root of 9 times by square root of 5
then square root of 9 is 3
and its 3 times square root of 5
ya
yea
got anything else? im bored cause no one answered my questions in the help channel
i could help
ohhhh
just 8?
then square both sides
wait what
basically
if u devide both sides by 2
nothing changes
but it becomes more simple
easier to solve
so final answer is 8?
not sqrt(x)
pythagoras
this channel is taken go to #help-5
ohhh wsit
ok
10 = 7 + 3 <==> x7 both sides is 7(10) = 7(7+3)
2sqrtx = 16
÷2 both sides
sqrtx = 8
Closed by @raven 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.
hey can someone help me with a.
im confused what its asking me to do
long division
yes but
like
what divided by what
well i know
but
if i do will it turn into the form a/x-1
do u know how to devide that thing by x-1?
yeh, do the division
yeah
do it
okay im back I got x^2 + 3x + 8 + 9/x-1
thats it
huh
x^2+3x+8 is P(x)
oh
and a is 9
so its just weird wording for solving long division
uurrrgghh
thank u tho
haha
.close
Closed by @hoary bluff
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 I get some help with question 1 please? I have done the base case but how do I make use of the orbit stabiliser theorem (or its corollary) in the inductive step?
@vast rover Has your question been resolved?
@vast rover Has your question been resolved?
@vast rover Has your question been resolved?
@vast rover Has your question been resolved?
@vast rover Has your question been resolved?
Closed by @vast rover
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.
"Assume that f is uniformly continuous on (-∞, 0]. Also, assume that f is uniformly continuous on [0, ∞). Show that f is uniformly continuous on the entire ℝ."
how do i show this
use continuity definition
to show that f is continuous at 0.
try to start from f(0)
then f is continuous on all R
yeah, i suppose i only need to show it is on f(0)
well all other values have already been assumed to be true
x=0
what about y
you don't know what f(0) is, f is an arbitrary function
Uniform continuity tells you for any epsilon there is a delta that works for all x in those two intervals
Take the minimum of the two deltas you are guaranteed
And rejoice
what exactly is the y then
you don't know? y = f(0)
i thought we had x and y because of mutiple dimensions
it doesnt matter and you dont know it
yeah lol
@desert musk
There’s no need for limits either
nw, help is always appreciated. The left/right side limit approach would work if it were continuity instead of uniform continuity :)
@desert musk what have you written so far?
Because f is uniformly continuous on (-inf, 0]
For all epsilon > 0 there exists a delta1 > 0 such that for all x if
|x1-x2| < delta1 then |f(x1)-f(x2)|<epsilon
Now apply the same definition on the other side of the interval
The line about x<0<y is unnecessary
another??
what?
i just never really feel done when i do epislon thing
you just write down the defintion and say now its proven
mind showing what you have?
I'd split it into:
Let x,y e R. we want to show that
|x-y|<delta ===> |f(x)-f(y)|<eps
yes
if x,y both in the first interval, then it's true since delta ≤ delta1
but i never feel like nice i got it when i do these sort of questions
you just write down the defintion and say "now it holds"
and x,y both in the second interval then it's true since delta ≤ delta2
hm, well have you shown that it actually holds?
see im never really sure if i have
i dont have a picture in my head of what im doign when i do this
k a sec I'll switch to pc
here we know that f is uniformly continuous for all R\{0}
now if we let x to be in the first interval and y to be in the second, we'll need to show the same
it is correct x and y just a points
that are some distance away from each other less than epislon
just like in the normal continuity but than y is instead of a?
oops I switched delta epsi
That’s not the only issue
We have uniform continuity
There’s still an issue
there exists delta, such that for all x, y
Not the other way around
what am I doing lol
can you draw me a visual graph of it
it'll be more helpful if you get used to the abstraction
I don’t think it’d be useful here
Now take the minimum of these two deltas
If. |x-y| < that then what can you say?
Was telling them
i tried nevertheless
yea the eps-delta rectangle is what you can visually infer
then draw from x and y
up to the points on the graph
i think for my graph it doesnt even hold
but still
why are we letting it be the minimum of delta
?
here
you'll see once we regard the third case
x in the first interval and y in the second
then i wont learn
Because then it works for both intervals
i need to be able to guess the answer myself
Say one delta is 2
what is the rational behind it
since delta <= delta1 and delta <= delta2, delta applies for the uniform continuity of both intervals
Then we know we get both conditions
why is your "big" delta smaller than delta 2
big doesnt imply being the biggest?
we defined delta = min(delta1, delta2)
I can also add it into the first two trivial cases iyw
so you just the smallest delta of your two deltas
which ever one that is
so we write delta = min(delta1,delta2) now i am sure that i've picked the smallest delta. Why is that important?
i am learning
Mav
if you can answer questions
You are trying to show uniform continuity on (-inf, inf)
Write out what you must prove
That’s not important
but im still asking you it is important to pick the smallest delta
Yes it is important
and now why?

that f is uniformly continous at x =0
No
how is that not it
And that’s doesn’t have any quantifiers
I want you to write out formally
What it means for f to be uniformly continuous on (-inf, inf)
As that is what we are trying to prove
For a function f to be uniformly continuous on (-∞, ∞), it means that for any ε > 0, there exists a δ > 0 such that for all x, y in (-∞, ∞), if |x - y| < δ, then |f(x) - f(y)| < ε, regardless of how large or small x and y are
Yes and the last part doesn’t need to be included
The idea is that If |x-y| < min(delta1, delta2), then
|x-y| < delta1
And
|x-y| < delta2
So then you can consider cases of x,y
why is that true
?
5 is min of 5 and 7
oh nvm
well ok
so now we are saying that it is smaller than the smallest delta then it is smaller than all deltas?
Smaller than the 2 that we are given yes
So consider an arbitrary |x-y| with x, y in (-inf , inf)
If |x-y| is less than our minimum chosen delta
Well if x, and y are in the same interval then we’re already done
Because we’re given uniform continuity in each
So only considering now WLOG x<0<y which I think was written above
WLOG?
Without loss of generality
what does that mean
It doesn’t matter if it’s y < 0 < x
Or x < 0 < y
Basically since the variables don’t matter here
We can only consider one case as they are the same
So without loss of generality means we can ignore the other case, it’s the same
so
if 3 fruits either apple or banana at least two of them will be the same
and it doesnt matter if i take the case of the banana or apple
an example for WLOG @sacred sparrow
just wondering why you said 3 fruits
you just want to express that x,y e R but x and y are in the different intervals
Yes
It’s like saying, given two distinct numbers a and b
We can say WLOG that a<b
Right because otherwise b<a
And we can just relabel
alright
I'll put the solution for the case you currently write as spoiler here
idk it just feels weird doing these sort of things
yeah it may feel overly strict and formal at first
im just giving myself what i need to solve it by for exmaple saying less than episolon/2
only once you accept the freezing you'll start liking the cold water :3
feels like solving a physics problem and just given yourself the information you need
yop
you do these steps in reverse
above I first used the triangle inequality
to see that I need eps/2
I didn't know it beforehand
(well I partially did, but let's assume I didn't)
often you first rearrange |f(x)-f(y)| to find out what estimates you actually need
and we knew that |f(x)-f(0)| is less than epislon epsilon/2
because we said it was for any x and y
which also includes y = 0?
in (-inf, 0]
x and 0 are in that interval
that's why I chose f(0)
because 0 is in both intervals
yes, but the idea its that it has to be smaller for all x and y in the interval
which will also be 0
smaller than epislon/2 that is
ys
@desert musk 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.
Is this a quiz
!status
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
Closed by @misty lynx
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 really sure how to do this. Any suggestions?
@royal pawn Has your question been resolved?
@royal pawn Has your question been resolved?
@royal pawn 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.
small confusions i had when revisiting this proof:
- why is the sum going to be direct?
- what does it mean when it says "by uniqueness on 0 \in V"?
@nimble crane Has your question been resolved?
I think uniqueness refers to the direct sum
bad wording
Any vector in a direct sum can be written uniquely as a sum of vectors
Each term of the sum comes from one of the spaces in ur direct sum
(Up to order)
hm okay, why does that imply that T(xi) = 0?
ah
T-invariance tells u each term is in the cortesponding space from the direct sum
By uniqueness since Tx=0 each term in the sum for Tx ends up being 0
There's several ways to pose being a direct sum so perhaps there is a better way to think about it?
Maybe I am misunderstanding. I'm still trying to think that out myself tbh
hmm
I know from friedbergs linalg book that V=R(T)+N(T) implies V=R(T) oplus N(T). It is an exercise there at least.
Your direct sum is really a sum of restrictions of T to subspaces so maybe chaining some silly facts like that together might work.
In general for T from V to V where W is a T-invariant subspace you can show N(T restricted to W) is N(T) intersected with W.
This was also an exercise from friedberg.
Scratch this. This is useless nvm.
Could the null space of say T restricted to V_1 be in V_1 by T-invariance maybe?
Oh I think it's literally just intersection bs
V_1 and V_2 already only intersect at 0
Further intersections won't change that.
Same idea should generalize to the whole direct sum I think
so (N(T) intersect V1) intersect (N(T) intersect V2) is also 0?
apologies, but that doesnt seem obvious to me
It is a subset of V_1 intersect V_2 which u know is {0}
ah
got it
that makes sense
It also trivially contains 0 (so is a superset of {0}).
okay, then this seems to work
ty
.close
Closed by @nimble crane
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.
4C
I think you mean $e^{cx}$
Ah, ok
Oh, well y=0 is only a solution when the equation has no independent x terms or constants
Why not
Yeah, only when there are no independent x terms or constants
Just try putting y=0 into any random DE
4C
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
It is, because there are no independent x terms or constants
As in, each x term(if any) is multiplied to some derivative of y
What?
y=0 can only be a solution if BOTH of the conditions are true
Yeah, so this satisfies the conditions I said
How…
There’s no constant
And there’s no independent x term
It’s multiplied to the y’ though
Something like y’+2y”y+3x=0 for example
This can’t have y=0 as a solution
Or y”y+3y’+1=0
Yeah, which is why I said those two conditions
Lmao
Not sure how to go about the rest of the question
It implies y=0 is a solution, unless y is in the denominator
Yeah, and that y or any of its derivatives is not in the denominator
Unless im missing something
@torn jolt Has your question been resolved?
@torn jolt 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 don’t understand what’s going on here
so (in a slightly different form) we have
[ \int u v' , dx = uv - \int u' v , dx]
where $u$ and $v$ are both functions of x
cloud
(which is essentially the power rule in reverse)
so then the strategy is to split the integral into a product of two functions, one of which you differentiate, and one of which you integrate, to get a new and simpler integral back
So wait
Why can’t we let v = cosx?
Why does dv have to be cosx?
because our original integral must have one thing we call "u" and one thing we call "dv"
i wrote an equivalent definition up here, "dv" is really just [ \odv{v}{x} dx] where $v$ is a function of $x$
cloud
"dv" is basically the integrand for a function "v"
e.g. how if you want to integrate f(x) = say, x^2, you integrate x^2 dx not just x^2
it's basically a function times dx, except that the function is a derivative of another function, which we call v
e.g. if v = sin x, dv would be (dv/dx) times dx = cos x dx
if v = sin(x) then dv/dx = sin(x)
$$v=\sin x$$
$$\frac{\dd v}{\dd x}\dd x=\dd v=\cos\left(x\right)\dd x$$
Wait why is dv/dx being multiplied with another dx
ren
wait if the dx’s cancel out then why isn’t there still a dx next to cosx?
Wouldn’t it just be dv = cosx
then you rearrange to solve for dv and get cos*dx?
you mean cos(x)dx? yes
yes
the underlying logic behind the formula for a derivative
like why the formula is as it is
??
yes I think so
one second
ren
this is the formula for a derivative, correct?
yes
you get what df and dx mean right
Yeah tiny difference in function f over tiny difference in x
yes
well
then dv = v' times dx
and they cancel out
bc integration variable
and bc it's a LIMIT not bc dx = 0
ren
yea
ren
okay??
I’m just trying to wrap my head around the treating the derivative operator like it’s a normal fraction
xD
i thought that's what we always did lol
the "d" here is just to represent infinitesimal change
dy/dx = y/x
no...
dy = infinitesimal change in y
dx = infinitesimal change in x
the "d" represents change
it's not MULTIPLIED
think of the d as a function
You cancel the d’s
ok
does it
okay
integrating, this, we get:
ren
yes
got it?
ren
Why do we want to solve for udv?
Isn’t uv the product
no, u dv is
we're trying to integrate u dv... uv is sitting there
@twin wolf FOCUS
Why integrate only u with respect to dv
we'll have to do a double integral
U and V are both functions of "x"
we don't integrate u with respect to dv; we substitute functions
e.g. for x cos x dx, we set dv = cos x dx and u = x
then, x sin x - int(sin x dx) = int(x cos x dx)
@twin wolf
look i don't seem to be able to explain this to you, sorry
@twin wolf Has your question been resolved?
Closed by @twin wolf
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 having trouble understanding this statement "Vectors, colinear with a line, make 1D real linear space"
Ik why they create a real linear space
the rest of the statement is "On the line exists a single non-zero vector colinear with the line. All +1 vectors are linearly dependent"
and it just says "There, 1D"
@brittle parcel Has your question been resolved?
is the dimensionality of the space unclear?
why it must be 1D
I don't know either
I'm having trouble fully comprehending this
ok, consider an arbitrary line in some vector space, R², R³ etc.
now which vectors are colinear with that line?
well colinear geometrically interpreted is the same as being parallel to it
so all vectors that 'go' in the same direction as that line are colinear to it
more specifically, if that line goes through the origin
then only all the vectors exactly on that line are colinear to the line
since they are the only vectors parallel to the line
the line could be elsewhere in the space of course
but the vectors colinear to it just form the same line, moved to the origin
so you can imagine that the set of colinear vectors to a line form a line on their own which is parallel to the other line.
and since a line is one-dimensional, that can be considered a 1D real linear space
because all vectors within that set
fulfill the properties of a linear vector space (addition, multiplication, laws, etc.)
@brittle parcel hope that made it visually a bit clearer
ones that are parallel or lying on the same line in said space
I think?
only parallel
well if they lie on the same line, every line is parallel to itself
if the line goes through the origin
then all vectors parallel to it
are the line itself
right
eg if we were to vis it in 2D:
this vector would be colinear to the line
this one as well
riiight
I see
or these three
now let me draw all vectors colinear to it as points:
which is just another line
since there are infinitely many vectors colinear to the blue line
I see, I see
in essence:
the red line = the blue line just moved
and a line that goes through the origin is a 1D linear vector space
you are going to see the same for other objects
a plane of vectors that goes through the origin is a 2D linear vector space
right, ty
.close
Closed by @brittle parcel
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've got a little problem I'm trying to solve for my own fun which probably has been solved centuries ago but still
what I'm trying to do is make a """"function"""" that takes an actual function "f" and an angle "alpha" and rotate f's graph by alpha radians
first thing I tried to tackle is making a function that takes a point and outputs a point alpha degrees clockwise to that point
I managed to do it without much trouble except for a few parts: when the x of the point xor the y of the point is negative then as you move through the values of alpha the point follows an ellipse instead of a circle, and more importantly: I don't know if it's even possible to make a desmos function that takes a point, let alone another function as its input
this here is what I've done so far
I don't know if there's much of a better way to solve this, there probably is, but what I did is make a function g that takes a and b, or the x and y of the point, for the x take the arccos of its x/hypthenuse to get the angle, add alpha to it then use cos to reverse it and get the ratio from the wanted x to the hypothenuse, then just multiplied by the hypothenuse to get the final x. I did the same for the y but with arcsin and sin instead of cos
I'm curious to see how the shape of the ellipse changes as I change the parameters now too, I never really learned any of this officially so I don't really know why the ellipse popped out there.
ping me if someone's interested
lovely
I once tried to create a function that has a fixed distance to another function, so that for any function, I can find a function whose values all have a distance of >=1 to all values of the other function
but that was awfully difficult and restrictive
in coooontrast to your question
which is quickly solvable :) @clever sand
but we'll have to slightly redefine it
I guessed that it's easily solvable
I just didn't know how so I challenged myself
sure, how so?
with the essence of linear algebra it becomes simpler
when viewing it from an analysis standpoint it'll seem difficult
k instead of seeking a function
that takes a function and converts it into a new one
k?
we'll instead let our initial function be given as an equation
an arbitrary equation involving x and y
unfortunately, I barely have basic terminology of linear algebra in my mind so it might be difficult to explain how
no problem
sure, go on
now, the graph for that equation is all points [x y] for which the equation is true
and we want to rotate each of these points [x y] by some angle a
which we can express in linear algebra:
as a product of a vector with a rotation matrix
meaning Rotation * Coordinates = Rotated_Coordinates
as I said
I haven't got the faintest clue what vector multiplication is
I mean I do understand what you are doing though
ok interesting
dw, I'll explain it in a different way in a sec
ok
you may accept that for now :D
the matrix multiplication yields us: x' = x*cos(a)-y*sin(a)
and y' = x*sin(a)+y*cos(a)
now why would that have any use?
well if you now take some arbitrary function, say ```
x+y = 5
which is just some random line
we can substitute the x with the rotated coordinate x'
and y with y'
x*cos(a)-y*sin(a)+x*sin(a)+y*cos(a) = 5
and now, we have the rotated graph by an angle a!
is that how you calculate a rotation usually?
ys in R²
well the issue will be that you can't necessarily rotate most types of functions
whereas the principle of "let's just rotate every single point instead"
is applicable for arbitrary functions
they don't have to be continuous or anything
sry gtg
what I did was a function that takes a specific point and outputs the rotated point, could you just use that function and do the matrix thingy using that (sorry I don't know exactly how that works so I'd like a clarification if that won't work) [I'm talking about the first line in the picture]
but if you want to know why these are the rotation values
you can search for "point rotation in 2D or R²"
ok thanks :)
how do I implement that in desmos if that's possible? I doubt it supports stuff like that
just curious
only in part, because it restricts our function outputs
it'll only work for continuous functions and they aren't allowed to rotate far enough to potentially have 2 outputs
anyway bye, I guess I'm gonna learn linear algebra now from random sources because I'm intrigued
thanks
so the method works, yes, but it'll only cover a small sample of possible functions
it won't require algebra btw
it's just sin & cos
for rotating an arbitrary point
nywys wish thee good luck, like the experimental spirit
🦇
I'm more intrigued as to what the hell matrix multiplication is and vectors and all that
I've been hearing it thrown around in a variety of contexts so I'm curious as to what it holds
cya
.close
Closed by @clever sand
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 help solving this integral
a u-sub makes this become a little bit nicer integration by parts
what u-sub should i use?
I thought to try (x-pi/2), but that doesn't take care of cos(nx)
i think either way you'll need to use two integration by parts
save the u-sub for later, and go with integration by parts first
Remember that pi is not a variable, and it can be moved outside with the 16
(the pi in the denominator... the one in parentheses is stuck for the moment)
@willow sundial 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 can't use discord on that computer so I had to take pic from another device
<@&286206848099549185>
@vast haven Has your question been resolved?
@vast haven 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 we find (rs)^11 in D6 hexagon without brute force? r is rotation ccw, and s is flip across x axis.
Split it
The dihedral groups obey:
r⁻¹s = sr
(rs)^6+5
rsrsrsrsrsrsrsrsrsrsrs
You can pass r through any s, just take the inverse when you do
they split it for you
@fathom saddle Can't you split it?
rs^(6+5)
Ok ya i get it
rsrsrsrsrsrs rsrsrsrsrs
so u can write rs ^6 + 5 right
make sure its (rs)^(6 + 5)
dont forget parentheses
rest assured this is the first time youve seen that
whats that supposed to do now
@strong pawn Since rs^6 and rs^5 are consecutive we can simply it to e (rs)
????????????
rs^(6+5) -> rs^6 * rs^5
Ya so now we got rsrsrsrsrsrs and rsrsrsrsrs
and yeah thats the same as rsrsrsrsrsrsrsrsrsrsrs
then how tf do we get e (rs)
Do you know that r^6 = e
Yeah
s^2 = e
Cuz if u rotate it 6 times u get trhe same thing
And if u flip it twice u get the same thing
But then doesn't it change because they are not together
They are separate
rsrsrsrsrsrs
Oh
What I did was r(sr)^4
becomes r(sr(sr)^3)
That simplifies to r(s^2r^2)
@strong pawn Now what can be evaluated
where is this from
i dontget it
so rn we goet (rs)^11 = (rs)^(6+5) = rs^6 * rs^5 = rsrsrsrsrsrs * rsrsrsrsrs
Oh sorry I got it from rs^5
Yeah but we know r^6 = e already
So now we only have to worry about rs^5
(rs)^5 = rsrsrsrsrs != r(sr)^4 = r srsrsrsr
rsrsrsrsr
So this is a rule I like to remember, useful for breaking down dihedral groups. In this case, we can use it to show rsrs = e
For retiring?
that sounds wack
Dam u hate me a lot
is it ok if u elaborate?
i dont get ur "pass r thoguh any s"
i do know a theorem
r^i s^j r^k s^l = r^(i-k) s^(j+l) if j = 1, and r^(i+k) s^l if j=0
but tahts only for rsrs
That's just true in any dihedral group. rs = sr⁻¹
@strong pawn Has your question been resolved?
Closed by @strong pawn
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 help me figure out what I'm missing for this problem?
@quick fox Has your question been resolved?
<@&286206848099549185>
you integrated with respect to V not t
I don't have time in this problem so how would I solve if I used V = -gt? What would my new bounds be?
you would just add -g to the result
and keep the rest
new bounds would be 0 and t
t being the time at which the velocity is measured
Do you think there's a +C involved here where the mass of the raindrop at t = 0 is the initial mass? Or is that already accounted for?
the + C is related to indefinite integrals
specifically because there is no starting point
you could have a starting time
t0
Closed by @quick 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.
What logarithm rules are being referred to here?
or arctangent rules?
Ok i have made signifcant progress
But I am still struggling with the bottom portion
from the second = sign to the third equal sign, it looks like ln 2 = (1/2) ln x
how would you solve for x?
maybe multiply the 1/2 over
so 1/2ln(2) = ln(x)
and then
exponentiate both sides
so e^1/2*ln(2) = x
is what I thought
i think you have to multiply by 2 to get rid of the (1/2)
actually, i think this is still wrong
2ln(2) = ln (x)
e^(2ln(2)) = x
then bring the 2 in
x = 2^2 = 4
ah no because remember exponent rules: x^(yz) = x^y * x^z
yes
can you find out a way to combine all of the logs in the question?
hint: use log rules
yeah so 8 should go in the box
ok thanks
that answers my questions, I see what they were doing now
the way its ordered with all the steps disjointed makes it hard for me to parse
yeah tbh i kinda dislike those problems too
np!
.close
Closed by @wanton basin
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 help me rq with this word problem i dont know how to start it off
0.9^3*807

