#help-36
1 messages · Page 135 of 1
alr lemme try solving these rq
alr so
remove the x^2 and 3x as they both end up to 0
and y = -4
so C
(0,-4)
now what if i rearrange the equation for x
since i know the value of Y
x^2 - 3x = 0
not sure what happened here
A and B are quadratic formula/whatever other way you solve quadratics
ohh
i moved the 4 to the other side
and got rid of it
as y = -4
4 -4 = 0
should i bring the -4 from y over to make it 8?
then solve as you said quadratic form?
i have no clue what you are doing
you have that y=0 for A and B
so do x^2 + 3x - 4 = 0
and apply the quadratic to that
that's it
oh
yeah mb my brain aint braining
lemme solve this rq quad form
-4 and 1
so
(sorry took a bit, got off track a bit)
so (-4,0) for A
and
(1,0) for B
@serene rain Has your question been resolved?
(-2/3,-4) is my answer
perpendicular means the slope changes so
y = -3x+1
plugged in first the x to solve for y
then vise versa
correct?
@serene rain Has your question been resolved?
yep
actually, solve for y in terms of x in the first equation. Plug into the second and solve for x. Once you have your x values you can solve for y
This is how you solve simultaneous equations
@serene rain Has your question been resolved?
Which one
@serene rain Has your question been resolved?
Which one
Cause you just factor and the multiply
I mean subtract
Like for a you can factor the denominator to (x+3)(x+2)
Theb multiply the right side by x + 3
And just x squared minus three subtracting x plus 3
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.
Are two lines/rays perpendicular when their orientation is a 90 degree difference from eachother
And do they have to form a vertex
that is correct
Closed by @flat ravine
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 explain how to solve this??
it says i have to write the slope intercept form of the equation of each line given the slope and y-intercept
y=mx + b is what slope intercept form is
where m is the slope and b is the y-intercept
Closed by @minor yoke
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 know the statement is wrong, but i don't know how to justify it
is because is addition and not multiplication, but i don't know if that is a good enough answer
Square both side
justified ✅
Closed by @surreal kernel
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 can i find the area of an elliptical sector
can i parametrise the ellipse then express theta in terms of t?
yeah
equation of line or smth else ?
which theta ?
the angle from the x axis to the line that makes the sector?
i think thats what they did
?
that is the area of a normal ellipse
yeah i know that
yes you can try this
actually i think its easier to express it as a polar equation
since the equation are bad too,
then integrate it using the angle as the bounds
true
Closed by @manic echo
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’m finding the axis of symmetry for f(X)=2x^2-4x and when I plug it in to the equation to make -4/2(2) I get -1. But I’m supposed to get positive 1 on the answer key. This happened for a different problem too I was doing. Am I doing something wrong?
Yeah, you are supposed to flip the sign
For the record, the axis of symmetry of y = ax^2 + bx + c with a nonzero is x = -b/(2a)
Closed by @hallow night
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 think I'm having trouble solving this assuming the field in R
*is
so {0} is an element of $R^2 \cap C^2$
ƒ(Why am. I here)=I don't Know
if $v,w \in C^2 \implies v,w \in R^2$
ƒ(Why am. I here)=I don't Know
are you sure it is closed under scalar multiplication?
I think it is
Ok, if I have some scalar that is complex, will that change your answer?
no
why?
it will still belong to the space
but not the sub-space
the field I'm assuming is R though
so won't the scalar be from R
if the field is R then yes... but I would think the field here should be C
because we are talking about subspace of the C
oh
okay
if the field in C, then won't it still be closed
the element will still belong to $\C^2$
ƒ(Why am. I here)=lin-alg
no... because how can you get i(0,1) to be in R^2 (i.e., your R^2 would not be a vector space)
yes
you cannot
true... but sometimes it is easier to work in C because to disprove something is easier than to prove something
ok, thanks
got it , thanks
.close
Closed by @warm python
Use .reopen if this was a mistake.
.reopen
✅
I'm just working out the entirety of the exercies here, as I don't have a answer key
so {0} is an element as (0,0,0) satisfies the given conditions
a.0) give a more direct closed form expression of that set
a.1) deduce whether it's a vector space
Simplify their definition
it's the set of vectors such that $a^3-b^3=0$
ƒ(Why am. I here)=lin-alg
for the field $\R$
in the reals, a^3 = b^3 if and only if....?
ƒ(Why am. I here)=lin-alg
a=b
yep
ƒ(Why am. I here)=lin-alg
i'm not sure what you're doing
basically (a) reduces to asking whether the set
{(a,b,c) such that a = b}
is a subspace
ƒ(Why am. I here)=lin-alg
checking closure under addition
yeah, I will now
ah ok
$(a+d,a+d,c+f)$
ƒ(Why am. I here)=lin-alg
which satisfies teh given condition
yea
so it's closed under addition
right
ƒ(Why am. I here)=lin-alg
yea just be sure to also check that it contains the origin (it does)
That's the first thing I did
ah ok good
ƒ(Why am. I here)=lin-alg
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
and yes for (b) the key is that a^3 = b^3 doesn't imply a = b, as you said
every nonzero complex number has three cube roots
ƒ(Why am. I here)=lin-alg
necessarily
right, you can find a simple example
say $\omega, \omega^2, 1$
ƒ(Why am. I here)=lin-alg
the cube roots of unity
yeah
sure
.close
Closed by @warm python
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 do this?
I would start by finding the path length difference between the two waves at R
@sonic crystal 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.
are there any non-linear transformations that satisfy only additivity or only homogeneity?
all non-linear transformations i can think of satisfy neither
@ancient ginkgo Has your question been resolved?
@ancient ginkgo Has your question been resolved?
@ancient ginkgo Has your question been resolved?
found an article talking about this, hope it can help
$f(x, y) = (\sqrt[3]{x^3 + y^3}, \sqrt[3]{x^3 + y^3})$
risujemmaaja
i think this works for satisfying homogeneity but not additivity
thank you!
oh yea i just checked and it seems to work
thats crazy
thanks
np
@ancient ginkgo 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
Would it be subtraction because I would be subtracting 8 from both sides when I solve the problem?
yeah
.close
Closed by @smoky bane
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 do this question? No linear combination of the three vectors in U make it = 0
?
You need alpha,beta,gaama that makes equation 0 right
Closed by @peak kernel
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 am i suppoed to find this
do you know what supplementary angles are..
do you still need to know how to get the answer?
so ur saying its 180?
so 65
Closed by @rocky drum
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.
idk where to begin. please explain how you got the answer too
.close
Closed by @patent pike
Use .reopen if this was a mistake.
Pythagorean theorem btw
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 @grand beacon
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.
they said b is wrong
i think they are asking the value of f at the local maxima
basically, what is the maximum value this quadratic equation can take
like the y value?
i did that thro chatgpt made sure it was right and got 7/4
but it still said it was wrong
but i just put 7/4
@chilly beacon Has your question been resolved?
.close
Closed by @chilly beacon
Use .reopen if this was a mistake.
It probably wants a simplified answer.
!nogpt
Please do not trust ChatGPT or similar AI tools for mathematical tasks, as they often generate output which "sounds correct" but has numerous factual or logical errors. Use of these AI tools to answer other people's help questions is strictly against server rules (see #rules).
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.
Why is 8sinh(u) wrong?
it says the correct answers are 8cosh(u) and 8sec(theta) but why is 8sinh(u) incorrect?
.close
Closed by @peak kernel
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 conditional mean this is what I did:
P(X_1 = 1) = p(1, 1) + p(1, 2) = 3/18 + 5/18 = 8/18 = 4/9 right
and then
E[X_2 | X_1 = 1] = 1 * p(1, 1)/(4/9) + 2 * p(1, 2) / (4/9)
right?
which should = 13/8
but online someone posted this as the solution
what m I doing wrong
and for E[X_2 | X_1 = 2]
P(X_1 = 2) = p(2, 1) + p(2, 2) = 4/18 + 6/18 = 5/9
so
E[X_2 | X_1 = 2] = 1 * p(2, 1)/(5/9) + 2 * p(2, 2) / (5/9) = 8/5
and we can see that
E[X_2^2 | X_1 = 1] = 1 * p(1, 1)/(4/9) + 4 * p(1, 2) / (4/9) = 23/8
so var(X_2 | X_1 = 1) = 23/8 - (13/8)^2
this is so 

ngl I think the person who posted that solution online is trolling or something
it doesnt seem right
Frosst
wait shouldnt I find it for each? like
E[X_2 | X_1 = 1] and E[X_2 | X_1 = 2] seperately?
yeah but if you think about it, the expectation of X_2 given X_1 is 1 or 2
clearly should depend on the probability that X_1 is 1 or is 2
mhm so will the formula be different thn what I did?
cos if X_1 = 1 is very likely compared to 2, then the E[X_2|X_1 = 1] is "worth more"
it sounds like $\mathbb E[X_2 | X_1 \in {1, 2}] = P(X_1 = 1)\mathbb E[X_2|X_1 = 1] + P(X_1 = 2)\mathbb E[X_2|X_1 = 2]$
Frosst

this sounds very reasonable to me i think
wait shit
I copy pasted
2 of the same ones
lemme redo
(4/9) * (1 * p(1, 1)/(4/9) + 2 * p(1, 2)/(4/9)) + (5/9) * (1 * p(2, 1)/(5/9) + 2 * p(2, 2)/(5/9)) = (4/9 * 13/8) + (5/9 * 8/5) = 1.611
P(X_1 = 2) = p(2, 1) + p(2, 2) = 4/18 + 6/18 = 5/9
that's right ok
all of it?
just that part it's hard to read
my question is why does it just c ancel
what cancels
Im so confused rn
Frosst
right
this is how much on average is X_2, given X_1 is either 1 or 2
but look at the support
X_1 can only ever be 1 or 2
should we have done it seperately?
like imagine a coin is coloured red on heads and blue on tails
right
and X_2 tells you the colour
and X_1 tells you if it's head or tails
we flip the coin
i tell you "the coin landed on either heads or tails"
well no shit sherlock
😭
I think the question wanted me to find E[X_2 | X_1 = 1] and E[X_2 | X_1 = 2]
came across another solution

thats what I was trynna do here
yeah
i think it's right
E[X_2] = 1*(1+2)/18 + 2*(1+4)/18 + 1*(2+2)/18 + 2*(2+4)/18 = 1.61
Closed by @fathom stream
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.
@charred raven Has your question been resolved?
@charred raven Has your question been resolved?
<@&286206848099549185>
@charred raven Has your question been resolved?
@charred raven Has your question been resolved?
@charred raven 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.
help
did you use chain rule?
where
i dont think so
i dont know how to get vector u(t)
you need to calculate the derivative of f(t)
you don't need u(t) for all t
if they gave you u(3) and u'(3) it's cause they're enough to answer the problem
oh
u(t) . v(t), how do you differentiate a dot product ?
am i able to do the derivative of vector u(3) dot the derivative of vector v(3)
no
this?
so
i can still use u(3) and v(3) as long as i use this right
sure
okay
i got 8t^3 + 7t -19
do i need to plug in 3 into those t variabkles?
im confused because i already used the u(3) and v(3) to differentiate
oh nvm
.close
Closed by @jaunty sluice
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.
.close
Closed by @warm hemlock
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
How do I solve this? First step is to find X right?
I did 36x-1+134x=169 but that did not work..
And this is my weird drawing idk if it’s wrong 🥲
what was your x value?
Like 0.97 or smt

Closed by @smoky bane
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 could I use a ti-84 plus CE to find one zero of this function: f(x)=5cosx+2/5x
@midnight warren Has your question been resolved?
put it in a graph and just go on calc - zeros
i have a ti 84 really old but thats what you do
you might need to adjust the scale
but thats just it
when I plug in 5cos(x)+(2/5)x it's giving me a straight line
my window is xmin=-20 xmax=20
ymin=-20
ymax=20
I know it's supposed to be a cos function so idk what I'm doing wrong
when I graph it in desmos it's just fine
no change it's still linear for some reason
how does it look in the calculator
similar to y/x
are you sure you inputed everything correctly
trying to put a pic in here
I can't find this text channel on my phone for some reason??
check if thats the right plot and everything
if everything fails try like restarting the calc
i gtg now tho
that calculator has 3 different plots
I see them at the top
just check if all the other ones are empty
lol how?
i gtg tho
ok
good luck and im sorry
Closed by @midnight warren
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 the difference between n-dim real coordinate space and n-dim euclidian space? i want to be sure my notion is correct.
I'll look it up again, but iirc Euclidean just presupposes the Euclidean dot product, whereas you can have spaces of R^n with other inner products defined
Depends on how you define them
i assume you are using the distinctly appearing terms "dot product" and "inner product" to coincide each other while denoting the same definition
thank you though
I mean the dot product as the standard inner product
so essentially; in 5 year old terms, you meant to say dot product twice in the sentence
can you elaborate please?
im glad there is more than one person in this server.
Sort of. Just that the Euclidean space has the specific inner product we usually call the "dot product", but you can have the same underlying vector space with a different inner product. But yeah, you can think of it as meaning other dot products.
i see.
and as an informal notion in differentiating the two, would it be that euclidian space denotes physical, "space"; and real coordinate space is a way of "graphing" to represent positions of vectors (n-tuple cartesian coordinates) on thet eucildian space?
Euclidean space doesn't really denote physical space. We can use it to represent physical space in a non relativistic context, but that's not it's sole purpose
@fathom zinc Has your question been resolved?
That can work if it makes sense to you.
An inner product space is a vector space with a choice of an inner product, much like you choose the field over which your vector space is defined.
The Euclidean space is physical in origin, as it comes from Euclid's postulates, used to describe the only geometry that made sense at the time. That is, a geometry where we can measure angles and distances as we could in the physical world, so flat space without weird curvature.
In this sense, the Euclidean space is an inner product space where we chose the dot product (multiply corresponding coordinates together and add everything) for our inner product.
On the other hand, the space R^n is a bare vector space : we haven't made the choice of inner product yet, but it could be any, not only the dot product as you learned.
While saying that the real coordinate space is a way of graphing vectors of the Euclidean space isn't false per se, I do feel like it misplaces the reason. We can represent positions of vectors in Euclidean space as n-tuples because the Euclidean space is constructed from the vector space R^n, on which we added a notion of distance through the dot product.
it would be extra helpful if you'd attach what your notion of the Euclidian space is, so I can have a reference!
I see!
although it may make sense to me, I don't think it will work
given that there are opposing views of 'abstract' euclidian space
i seek a reliable definition.
although I am familiar with the ambiguity of the terms regarding informality and formality
Euclidean space is just $\bR^n$ with dot product as its inner product.
SWR
okay, sure. Thank you!!
@fathom zinc Has your question been resolved?
Closed by @fathom zinc
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 with part B? What do I say for it?
draw all points on the graph
Yeah I have
Is there a right or wrong answer for these questions?
Like just by looking at it
Because in part d, it asked to calculate the correlation coefficient then compare the answer to part b
@elfin quartz Has your question been resolved?
.close
Closed by @elfin quartz
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 do any of this question
ok so lets start with part (b)
when they say initial temperature
what does that suggest
yes, and you know T is a function of time t
as time increases, the temperature decreases
as the value of t increases, the value of T decreases
but where does 't' start from
69 i think
nope t itself starts from 0
at the 0th second, just when the coffee has been served
then 1 second later, the temperature is lesser
a 1000 seconds later your coffee is even colder
so how do i do the rest of the question
isnt the number before the 1/2 always the initial value tho
nope
the initial value is when t=0 (or whatever the variable in the function is)
T is the temperature as they say. T(t) means the temperature changes with time 't'.
thats how functions work
so answer to b is 90
yep
how do i graph this
now for graphing it
do you know what the graph of a^x looks like? (a being any number)
like the general shape of the graph
yep. this is the case when a>1
so like 2^x
it will increase exponentially as x increases
but what if a<1
like it is in your case
(1/2)^x
or (1/2)^t whatever, variable doesnt matter
isnt it like thsi
yep perfect
now all you gotta do is add some details
such as where does the sketch of the function intercept the y-axis
(you calculated this in part (b) )
90
yep so when 't' is the 0th minute, the Temperature is 90 degrees
in other words
when x=0, y = 90
so you mark (0,90) on the point where the curve intercepts the y axis
ok but what else do i do
you also gotta make sure your curve isnt going to the left of the y-axis
since that would mean x<0
or time< 0
and time cant be negative
so instead of going all the way, your graph ends at x=0
ok but how do i graph the rest of it
you have a curve so far, you have the point where it intersects the y axis
and youve made sure time isnt going negative
thats your curve
if you want you can add one last detail:
as "t" keeps on increasing.. there will eventually be a time where t is so large that 69(1/2)^(t/30) will become so incredible small that your graph will turn into a straight line at y=21
as you can see here, at the end, the graph is almost a straight line
so you could draw out a dashed line indicating that at any point, the temperature of the coffee doesnt go below 21 degrees
thats the entire graph
you dont need to make the axis with 0, 50,100,200 etc as long as you mark (0,90) on the graph
and if needed, (0,21) indicating where the graph becomes a constant
is there not some table of values or something tha ti can follow
to graph itaccurately
you do that when you dont know what the shape of the graph looks like
but since you already know that
i mean you could use the table of values method if you want to make the "shape of the curve" pass through all points it should
is there a parent function table of values for exponential functions i can follow
you take different values of "t", and you find the corresponding value of "T" for that specific "t"
then you mark (t,T) on the graph
theres no universal table of values
you make the table of values
in this particular question, the table consists of some test values for t, and the corresponding values of T
you mark a couple sets of points (t,T) on the graph and connect them
but as i said, you dont need to do that if you mention (0,90) on the graph, and that y=21 is the least it goes by marking (0,21) on the graph as well
thats what brings the accuracy
ok
(d) should be pretty easy given what youve learnt so far
Closed by @merry lodge
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 to find the determinant of the second matrix. Given the result of the first matrix.
This has to be done by applying determinant properties.
But I don't know how to proceed any further.
try expanding along the first column instead of the first row
@slate meteor Has your question been resolved?
I did both
And by expanding the first column I got a determinant with 2 equal rows, so that's 0
Not really, i just don't know how to proceed.
I need to get something out of the determinant of the 3x3 matrix that I can compare to the 2x2 matrix determinant.
I will try to expand the 2x2 matrix determinant and check if I can get smth
Ok, I believe now I can do something
Closed due to timeout
Use .reopen if this was a mistake.
It seems correct to me, but I don't know since I don't have the correct answer to check.
.reopen
✅
Well technically if I pick some N for the a,b,c,d I could check it by myself right?
mmm nope
@slate meteor Has your question been resolved?
Closed by @slate meteor
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.
does it matter how i write the solutions?
as in, for the case gama is not equal 0, not equal 1, can i just write
or can i also write a row of the solutions?
as in ${ (-3\gamma+2/\gamma, \gamma, \gamma) } $
@snow karma Has your question been resolved?
the convention is to write it as a column vector. If you want to express it as a row vector you can use the transpose operation, like $$[-3\lambda + \frac{2}{\lambda} ;;;; \lambda ;;;; \lambda]^T$$
Crystopher
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.
property:
If two intersecting lines of a plane are parallel to another plane, then the planes are parallel.
I don't know when to use n , c or element of symbol
I mean I don't understand how to put the sentence (the property) in symbols
What exactly is your question?
How do I see from the text I have to use these symbols?
Do you know what the symbols mean?
Yeah, so you want to identify the variables of the property.
“Two intersecting lines of a plane”
Already you know you need to define 2 variables for the lines and a variable for the plane, the 2 lines must intersect and they lie in the plane (are a subset of the plane)
“parallel to another plane”
Now you also have another plane in play, and both lines are parallel to the new plane
Oh yea I see now thanks
but ive another question
whats the diffrences between c and E ?
you know the c with the stripe
I feel so dumb now ;-;
$x \in V$ means a single element $x$ is a member of a set $V$
shsgd
e.g. 1 € R, where R is the set if real numbers
so its like E is one part
and C is the full part of something?
$y \subset V$ means a set of elements are members of a set $V$
shsgd
e.g. {1,2,3} c R
Closed by @cobalt vigil
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 direction cosines
What do you mean by that?
what's your native language, maybe I can find the word in that language
German
,w direction cosines
Richtungskosinus
,w direction cosines in German
heard of this>
What's that?
esssentially a way to describes slopes in $\R^3$
ƒ(Why am. I here)=I don't know
I think with describe the position it more means to talk about symmetries, if the origin is in included etc.
So this is symmetric to the x3-axis
Also, it doesn't include the origin
It isn't symmetric to any coordinate plane or anything like that
Well I don't think it asks us to calculate the direction cosines
@faint locust Has your question been resolved?
.close
Closed by @faint locust
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.
Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.
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 simplify this
Closed by @thick ravine
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 prove there exists 2 numbers a,b such that:
(2^a - 2^b) | 2017
I understand the Pigeonhole Principle, but i just don't know how to prove it
the solution says I need to think that there is a finite amount of remainders for 2017 ({0,1,2,...,2016}), but I don't understand how to prove it
as in that necessarily there will be 2^a - 2^b | 2017 then
how do you that for sure?
2017 divides the other thing
i didn't know it before looking at one of the solutions myself
so if 2^a - 2^b | 2017 either (a,b) = (1,0) or 2^a - 2^b = 2017
uh
are you sure you copied the problem right
i assume this is from some olympiad right
yes
from Linear Algebra 1 homework number 2
oh
first question by the way (4 parter)
also since you just need to proof there exist a,b 2^a - 2^b | 2017 isnt puting (a,b) = (1,0) enough
but that would be 1 | 2017?
that’s right, and it’s true
what do you think 1 | 2017 means
yeah but it's not divisible by 2017
I don't follow
a|b means the opposite of what you think it means
oh
I did write it wrong
"prove that 2 numbers a,b, makes:
a^2 - b^2 is divisible by 2017"
didn't have much experience using it so I forgot it's opposite sides, sorry
it’s okay, it happens to the best of us
you want a^2 - b^2 = 2017k
=> (a+b)(a-b) = 2017k
can you find some a and b which make it possible
you want a factor of 2017 on lhs
a=+-b?
no
then no
(2016,1) works for example
how did you get there?
cos then a+b = 2017
(a+b)(a-b) = 2017*2015=2017k
since (a+b)(a-b) = 2017k if we can let either a+b or a-b = 2017m the 2017s cancel out
but do you know how I could use the Pigeonwhole principle for this question instead?
oh my bad, I meant:
2^a - 2^b
ah ..
yeah
this is what I had
it's a reasoning that there must be 2 numbers 2^a and 2^b exist that do make this possible to get 2016+1 or something similar
since that's their remainders
a=b
a
wow
its easiest wiht just basic number theory
i found a similiar question in some pdf
let me try to find a pigeon hole solution
wdym?
heres one
i understand it now
yeah makes sense
Closed by @snow karma
Use .reopen if this was a mistake.
i dont get it?
i dont see the value in the theorem i mean
i see the see it, but i dont see an application like Pigeonwhole principle
what?
if i asked to you to find distinct (a,b) such that 2^a-2^b is a multiple of 2017, how woul dyou do it?
do you know modular arithmetic?
like the solution did using Pigeonwhole principle
no?
you would have to try every 2^a from 0 to 2016
oh to find
not prove existance
yeah
ok youll learn it on your olympiad journey
once you start learning number theory
will it be in Linear Algebra?
do you know what year as a math major?
but not classical linear algebra
oh are you doing this for olympiad or college?
im still a student idk
college
idk when ever you start number theory
does it get easier to do proofs?
wdym?
we still are learning group theory in a parrelel course
i mean im 3 weeks in and i have to look up proofs
for my homework
if you practice proofs writing proofs will become easier ofc
it's so weird because these are so hard
but does it become normal?
or do you too need to look up solutions for homework problems?
itll become normal
okay
well sorry for bothering you like that
youre good
ty for your help mate
np
.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.
find all $a \in \mathbb{R}$ such that $\\\sum_{n = 1}^{\infty} \frac{(1+a)^n}{n}(x-2)^n\\$ has radius of convergence equal to 2
938c2cc0dcc05f2b68c4287040cfcf71
bruh I was talking in other help channel because I thought it was mines
mine closed due to inactivity
basically after taking root test
I get this
but I think I made a mistake
or does that mean that
,, \lim_{n \to \infty} |1 + a| < \frac{1}{|x-2|}
938c2cc0dcc05f2b68c4287040cfcf71
@gentle zephyr Has your question been resolved?
@gentle zephyr Has your question been resolved?
can u state the relation of n with the other vars?
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 am stuck on this question, the answer I am getting is not even on the line. I can't figure out where I am going wrong.
@tired galleon are you still around to help? I know you said to use this formula
$$\mathcal{L} (x,y,\lambda) = f(x,y) + \lambda g(x,y)$$
TheDragonOfFlame
But it isn't in my textbook so I was trying to do it the way they do
But there shouldn't really be a z value, so I'm unsure what "f(x,y)" would even be?
Other than 0
is lagrange required?
this is called lagrange multiplier
bit of an overkill id say
ur missing 2 nablas
Yes, it says to solve using lagrange multipliers
hm, sure
That's just what the other guy sent, it isn't the formula I am using
I've been using $$\nabla f(x,y,\lambda) =\lambda \nabla g(x,y)$$
TheDragonOfFlame
Fairly sure in the first channel the original thing said the Q wanted him to use lagrange multiplier so I did lmao
yeah in that case its fine
Right, sorry
Forgot to say
Must sleep as I have been in a plane for too many hours today to stay awake any longer, sorry
But a comrade should get you to the answer 
Why is g=0?
set g(x,y) to 0, thats ur constraint
Wouldn't that be when they intersect?
Or wait what?
I thought g would have to refer to the point in some way
this is just the general methodology for lagrange multipliers
But if g is zero isn't the gradient of g also 0?
Meaning that gives no information on the Lagrange multiplier?
no
we set g = 0 as our constraint equation, let me link u a page that helped me when i learned this
g is not identically zero
g=0 means you restrict yourself to the level set where g is zero
Ohhh yeah I see
So the point where g=0
Ok yes
So, am I not doing that?
I thought I was kind of
Because g(x,y)=0 when x=4 and y=2
Oh but is it only true when I plug the points in?
i didnt look at ur work
lemme see
honestly i cant really tell what ur doing on that page, it looks like u flip flopped f and g tho
Do I need to solve for the multiplier and then use that to find y in terms of x and x in terms of y and then plug that into g(x,y) to get the values of each that make g(x,y) = 0? That's what I did for previous questions
f(x,y) is the given equation and g(x,y) is the square of the distance between them
Oh but I am trying to maximize the distance not the given equation
True
$f(x,y) = (x-4)^2 + (y-2)^2 \newline g(x,y) = y - 2x - 3$
just start again with this and use this
So the line is the constraint, I was thinking backwards
Ok just to check the steps. I find the gradients, set them equal, solve for the Lagrange multiplier, find each variable in terms of the other, and then substitute them into the constraint formula g(x,y) to find the point?
find gradients of f and g
multiply grad g by lambda
set vector components equal
solve for lambda in each equation
set both values of lambda equal
now u have 2 equations in terms of x and y, the one u just made, and the constraint g (set g equal to 0)
dude i gotta go outside, the sky is so nice, if u want i can check ur work later
just dm me or keep this channel open or smth
True 🥲 Gotta hate summer school
Thanks for helping
np, lmk later if u need help
I think I can probably get it? I'm having a tough time really grasping this concept for some reason
.close
Closed by @gilded flame
Use .reopen if this was a mistake.
.reopen
✅
show me ur work
ok so
Well the lamda equations are inverse, but the x and y relationship is the same






