ok lemme draw an arrow
#help-17
south flare
78 is not the answer
wind python
why
south flare
wind python
:,))
south flare
you just found the 78 part
south flare
we're looking for the green part
south flare
yes just you need to find the angle measure rn
wind python
i think to find the solution would be 180-12
south flare
no
don't forget that every quarter part has 90°
if you notice, we do this on a circle
south flare
wind python
Is that 900?
south flare
no 90°
wind python
Oh wait no it’s 90
south flare
it is 90
lol
so what should we do with these angles if we want to find the green part?
wind python
Add them
south flare
of course
wind python
78??
south flare
yes
wind python
Wait whaaaatt
wind python
I am looking
south flare
covers all these angles
wind python
Yes
wind python
Ohhhh
south flare
so 90+90+78 = 258 must be the answer
south flare
yesss
wind python
315
south flare
yes
wind python
AAAAAYYY
wind python
Give me one more plz
south flare
i have to go rn
wind python
O
wind python
Okay (:
south flare
see you later Frog
wind python
Thank you for helping me understand bearing, I appreciate it so much
south flare
Thank you for helping me understand bearing, I appreciate it so much
you're welcome
wind python
I hope you have a good day
south flare
I hope you have a good day
you too
muted needle
need help with this trigo qn
vocal sleetBOT
need help with this trigo qn
onyx nymph
In a triangle all the angles together= 180
You can find the angle ACB by doing arctan(12/5)
And you know that the angle ABC is 90 degrees
muted needle
You can find the angle ACB by doing arctan(12/5)
so I inverse tangent 12/5 to find angle ACB
then I take 180 degrees - 90 - angle ACB to find angle CAB
then I find the value of sin CAB
then I take 180 degrees - angle ACB to get angle ACD then I cos the final value right?
onyx nymph
Yep
south flare
isn’t there a shorter way?
there is
muted needle
what is it?
south flare
have you tried assigning lengths to line segments?
to the sides of the triangle
muted needle
I don’t get what you mean
south flare
like you can say AB = 12k and CB = 5k
thus
tan(ACB) = 12k/5k
= 12/5
becuse if you look carefully tan(ACB) = AB/CB
muted needle
tan(ACB) = 12k/5k
yeah I know that
muted needle
AC is going to be 13k
is it because of Pythagoras theorem
south flare
x² = 25k²+144k²
muted needle
Pythagorean theorem
ok
muted needle
then for sin CAB I take CB / CA
muted needle
I think I get it now
muted needle
tysm
south flare
you're welcome
muted needle
I was waiting for someone to help me 😂
south flare
I was waiting for someone to help me 😂
ahaha
muted needle
can I add you bro?
muted needle
thanks
south flare
np
muted needle
I sent a request
south flare
I sent a request
i accepted
south flare
I’ll close this post now
okay see you later
muted needle
.close
vocal sleetBOT
muted needle
okay see you later
see you
vocal sleetBOT
Available help channel!
brisk cape
Help
muted needle
should be correct
muted needle
range is definitely wrong
how
dim stirrup
How so
orchid wren
Question 176 right ?
muted needle
Question 176 right ?
yeah
dim stirrup
175
orchid wren
300×0.87^4x
dim stirrup
It would still be 0 to +inf for 176 though
dim stirrup
orchid wren
It would still be 0 to +inf for 176 though
No
@dim stirrup Sry i was speaking of 176
dim stirrup
dim stirrup
The range for 176 is still 0, +inf
orchid wren
The range for 176 is still 0, +inf
Yeah i didnt use -ve
dim stirrup
Yeah i didnt use -ve
What is -ve
muted needle
What is -ve
should be negative gradient
muted needle
The range for 176 is still 0, +inf
as you can see in your desmos graph, the gradient is going downwards
brisk cape
That means range would be -
dim stirrup
Range is still (0, inf)
muted needle
That means range would be -
yes
muted needle
Range is still (0, inf)
why do you say that?
dim stirrup
why do you say that?
Possible values of y still range from 0 to inf
f(-inf) = inf
f(inf) = 0
muted needle
Possible values of y still range from 0 to inf
the range could be from any negative number to 0
dim stirrup
the range could be from any negative number to 0
the function 300(0.87)^4x cannot output a negative number if x is a real number
muted needle
however, if the y value is 0, there would be no gradient as its undefined
brisk cape
Was there anything else I missed for the problem before I go back to 176
dim stirrup
I believe the base should just be "1.05"
Other than that, everything in this image looks fine
brisk cape
Thank u
muted needle
I believe the base should just be "1.05"
yup
vocal sleetBOT
@brisk cape Has your question been resolved?
muted needle
should be fine
vocal sleetBOT
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Available help channel!
tawdry snow
Need help with D
vocal sleetBOT
Need help with D
vast shale
Need help with D
!status
vocal sleetBOT
Need help with D
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
1/4!/2
brave coral
at first glance i got ||1/5||
vast shale
at first glance i got ||1/5||
don't give answers
tawdry snow
I just did one over the number of arrangements
tawdry snow
at first glance i got ||1/5||
that's wrong
vast shale
that's wrong
you sure buddy?
vast shale
you shouldn't be
vast shale
how do you do
so
think about it
there are five starting numbers
with 4, 4, 5, and 6
it can not be less than 40000
3 is the only option
vast shale
and 1/5 of arrangments start with 3
tawdry snow
I mean the topic is permutations
brave coral
lisan could you give us the answers for a, b, and c
brave coral
a) 60 b) 48 and c) 36
good how did you solve for those answers
tawdry snow
so the first one I did 5!/2!
the second one I did 4x4!/2!
and the third one is 3x4!/2!
brave coral
know that the probability (or chance) of an outcome is
Probability = number of Favored Outcomes / Total Number of Outcomes
in the case of (d), what is the favored outcome
and how many are there
brave coral
so how did you get the final answer
tawdry snow
so the number of arrangments under 40 000
brave coral
which is?
brave coral
over the answer for (a), which is 60
tawdry snow
yes
brave coral
which wields a final answer of
tawdry snow
1/5
brave coral
ok
vocal sleetBOT
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neat pivot
Problem: A box contains 8 white balls, 7 detector balls and 5 black balls. Choose randomly until you get 2 black balls, then stop. Calculate the probability of choosing 3 white balls, those 2 balls
(The question was translated directly from Vietnamese to English using google translate; so, there might be misunderstandings with the terminology)
**Given answers: **
A. 147/5000
B. 149/5000
C. 37/1250
D. 73/2500
What I am stuck with: I don't know the solution to solving the problem, I don't know how should I proceed with it.
(My English proficiency concerning Maths is very low. Please use simple maths-related words if possible, thank you.)
vocal sleetBOT
**Problem**: *A box contains 8 white balls, 7 detector balls and 5 black balls. ...
@neat pivot Has your question been resolved?
vocal sleetBOT
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Available help channel!
storm owl
I need answers idk how to do
vocal sleetBOT
I need answers idk how to do
storm owl
jagged cargo
is this a test?
storm owl
is this a test?
Review thats do soon
I haven't been in class for like rhe last 2 weeks so idrk how to do and just need answers soon sorry
vocal sleetBOT
@storm owl Has your question been resolved?
neon plover
what test can i do for convergence here?
vocal sleetBOT
what test can i do for convergence here?
neon plover
i know it diverges by intuition but what test can i use
wait do i just compare it to ln n
nvm got it
.close
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vast basin
vocal sleetBOT
vast basin
Have I solved it correctly?
wary mantle
,w derivative sin(x)^(log(x))
winter thistle
almost, you forgot to multiply cotx logx by y as well
twin meteorBOT
vast basin
almost, you forgot to multiply cotx logx by y as well
Thanks a lot.
: )
worn bobcat
And you also need to subtract 1 from both sides after multiplying by y
worn bobcat
but I don't know why you wouldn't just subtract 1/y from both sides to begin with
winter thistle
And you also need to subtract 1 from both sides after multiplying by y
it's 1/y *, not 1/y +
worn bobcat
oh true silly me
vocal sleetBOT
@vast basin Has your question been resolved?
vast basin
.close
vast shale
@hollow lark
vocal sleetBOT
<@764108874042703902>
hollow lark
yea?
hollow lark
sorry to trouble you again
i'd be happy to help if i can
vast shale
if we have 5 cards: I, V, X, C, L, and 5 shadow cards
what are the permutations where exactly 1 card from IVXCL matches the shadow cards
vast shale
i'd be happy to help if i can
haha cheers mate
hollow lark
what are the permutations where exactly 1 card from IVXCL matches the shadow car...
so shadow cards means the same cards
vast shale
yeah
so this is what I thought
if we take the same way we solved the previous question
we could have 5C1 to select one card
and that would go into 5 spaces between the other cards
and there would be 4! ways of arranging the rest of the cards
which would give the answer to be: 5C1 * 5 * 4!
but apparently this doesn't come out to be 45
which is the right answer
hollow lark
ok
hollow lark
ok in this order
vast shale
and at the bottom we have shadow cards
exactly one card should match and the others should not
hollow lark
ok
so 5C1 to select the card that matches
and do dearrangement for 4 cards
do you know about dearrangement?
vast shale
nope
vast shale
ah awesome
vast shale
yup
hollow lark
both named a b c d
we need the permutations so tht no letter would go to its specified letter box
for that we use dearrangements
hollow lark
yes
if dearrangent of 5 then 5!(1 - 1/1! + 1/2! - 1/3! + 1/4! - 1/5!)
i think this is it
vast shale
$4!(1 - \frac{1}{1!} + \frac{1}{2!} - \frac{1}{3!} + \frac{1}{4!} )$
twin meteorBOT
Emploice Muswashans
vast shale
and this would be dearangement of 4 right?
hollow lark
and this would be dearangement of 4 right?
this is for four
vast shale
gotcha
hollow lark
if dearrangent of 5 then 5!(1 - 1/1! + 1/2! - 1/3! + 1/4! - 1/5!)
this is for 5
there is also another way to do the question
since its a small question
u can avoid dearrangment and substract the values
u dont want
hollow lark
ur welcome
dearrangement is faster
but u can also do it normally
if u need help doing it in a normal way let me know
vast shale
dearrangement is faster
yeah i definitely liked this much more
vast shale
cya!
hollow lark
see ya
vocal sleetBOT
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Available help channel!
soft field
Guys so can anyone explain to me why I'm getting infinity here when applying the formula to make a line?
vocal sleetBOT
Guys so can anyone explain to me why I'm getting infinity here when applying the...
soft field
Ping me if someone wish to help me out.
cursive turret
a vertical line is just x = some value @soft field
soft field
Yeah in my note too it says x = 1, but it is in the y axis right? So it's supposed to be y=1 isn't it!
Also why don't this formula work here? According to my teachers they say it works on any two points
I'm really sorry tho I'm really bad at maths
Ik it might be something stupid I'm talking about..
cursive turret
your line is x = 4, and any y. y does not depend on x.
the formula you try to use is for cases where changes in x will result in changes in y, which is not the case here.
cursive turret
sorry, x = 1 not x = 4.
soft field
Ah
soft field
your line is x = 4, and any y. y does not depend on x.
the formula you try to ...
Like can you provide an example for such case?
cursive turret
for whcih case?
soft field
Where I can apply the formula
cursive turret
try C->B
soft field
Hmm
cursive turret
or better C->A
cursive turret
A and B have x = 1, this is given.
every point on the line from A to B has x = 1 .
soft field
So what if it was like a and b has both x and y axis as 1?
Ah nvm
That's stupid to ask lol
Ok gotcha thanks bud
.close
vocal sleetBOT
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neat spear
Could I get help with a physics thing? I know it’s not exactly pure math but something is confusing me.
vocal sleetBOT
Could I get help with a physics thing? I know it’s not exactly pure math but som...
neat spear
So the calculation or formula to estimate how strong gravity is on a planet is dependent on the planets mass/weight and the radius from the core of the planet to the surface yadda yadda.
But… isn’t weight determined by gravity? Like so if you had a planet that was 4x earth’s size but same density etc etc, if you plug in 64x earth’s mass and 4x earth’s radius the gravity going off the calculators I have would make it 3.92x stronger gravity.
But wouldn’t that fact that gravity is stronger then make the planet have much more mass… and thus more gravity… which- you get my point?
Like volume doesn’t change but the weight/mass does. I know weight and gravity are different and all that. But now I’m confused.
vocal sleetBOT
@neat spear Has your question been resolved?
neat spear
No
timid ruin
can someone explain to me when something is convergent or divergent pre calc
flint idol
a series or a sequence?
actually that doesn’t really matter
convergent is just when a series or a sequence approaches a certain value
divergent is when a series or a sequence doesn’t approach a certain value but instead approaches infinity or just continues to alternate between numbers
vocal sleetBOT
@timid ruin Has your question been resolved?
empty frigate
i remember there being a formula
for some specific things like $\sum_{n=1}^\infty a^n$ there's a condition on $a$ that tells you whether it converges or not, but for a general sequence there isn't really anything better than ``if it approaches something''
twin meteorBOT
bee [it/its]
empty frigate
unless you mean the epsilon-delta definition but that's not really a "formula"...?
timid ruin
how do i know if it is approaching something
i thought if the ratio is less then 1 or greater then 1
empty frigate
well for a general sequence there's a lot of different tactics you can use, there isn't really just one approach
(and sometimes none of them work, like \textit{nobody knows} whether the series $\sum_{n=1}^\infty \frac1{n^3\sin^2(n)}$ converges)
twin meteorBOT
bee [it/its]
empty frigate
in the particular case of $\sum_{n=1}^\infty a^n$, which i now suspect is what you were thinking of, it converges if $|a| < 1$
twin meteorBOT
bee [it/its]
timid ruin
we find a using the 1/1-r formula right
empty frigate
...idk what you mean by "find a"?
it's just, if you have a sequence in this form
so for instance $\sum_{n=1}^\infty 2^n$ does not converge because $|2|$ is not less than $1$
twin meteorBOT
bee [it/its]
empty frigate
this is the case where $a = 2$
twin meteorBOT
bee [it/its]
empty frigate
but if you had $\sum_{n=1}^\infty 0.7^n$ (so $a = 0.7$), that does converge because $|0.7| < 1$
twin meteorBOT
bee [it/its]
empty frigate
in that particular case yes
or more specifically if the absolute value is less than 1
$\sum_{n=1}^\infty (-2)^n$ doesn't converge even though $-2 < 1$
twin meteorBOT
bee [it/its]
vocal sleetBOT
vocal sleetBOT
✅
timid ruin
.reppen
how does that even make sense
a conversion is when it is hitting to a certain number right?
empty frigate
yep
timid ruin
so any negative numbers will not be convergent
twin meteorBOT
bee [it/its]
timid ruin
ok i get it
it is the number that matters not the the negative or positive
if it -.76 it will converge rifht?
empty frigate
yeah basically
empty frigate
if it -.76 it will converge rifht?
yep
timid ruin
but if it is -3 it don’t combwege
alright i think i get the gist of it
so if it converges i use the 1/1-r?
if it asks
empty frigate
if you want the value it converges to then yes
stray prism
converges if | r | < 1
vocal sleetBOT
@timid ruin Has your question been resolved?
static granite
i havent learned how to do any of this, i dont know how or where to start
strange crater
what's your question?
vocal sleetBOT
@static granite Has your question been resolved?
static granite
what's your question?
idfk
this is so stressful
i dont even know where to start
wintry vine
i dont even know where to start
it basically defines what linear means
you know when you have an equation
of the form y = mx + n, where m, n can be any value
that is linear, because if you plot (x, y) on a graph you get a straight line
basically steady increase
whereas in a quadratic, it doesn't
vocal sleetBOT
@static granite Has your question been resolved?
mortal holly
Are there any methods except delta to find how many roots are there and what are their signs for a second degree 1 unknown equation
vocal sleetBOT
Are there any methods except delta to find how many roots are there and what are...
mortal holly
second degree 1 unknown equation... so... a quadratic
yes
mortal holly
i mean the reel ones
hallow plover
Their solutions are given with the quadratic formula, and the nature of the solutions from that formula is determined by the discriminant
so you need to check the discriminant to analyze what the solutions are
mortal holly
so you need to check the discriminant to analyze what the solutions are
Yes ik. Are there any other methods?
hallow plover
Nah, not really. Well, if you have access to a graphing calculator you can graph the function and check where it crosses the x axis
but analitically that's about it
vocal sleetBOT
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Available help channel!
deep mural
i have following equation $10^{23} - 10^j - 12 \equiv 0 \mod 17$ and next line is $1 \equiv 10^j + 12 \mod 17$. I don't get what happens in between
vocal sleetBOT
i have following equation $10^{23} - 10^j - 12 \equiv 0 \mod 17$ and next line i...
twin meteorBOT
ta
hard atlas
not maybe 10^32 ?
deep mural
nope
hard atlas
!original
vocal sleetBOT
Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.
deep mural
sure one sec
Find the smallest number with a sum of digits of 204 divisible by 204.
in class we discover that it has at least 23 digits and ends with 88, then we prove that there's one 8 among the rest of the digits, while others are 9s, then we get the equation above
also 204 = 17 * 2^2 * 3
the answer is j=5
it can be wrong but unlikely
hard atlas
yeah I dont know from where thats supposed to come
deep mural
but is the answer correct at least
hard atlas
no
hard atlas
well the starting equation was good
10^23-10^j-12=0 mod 17
or 10^23 -12= 10^j mod 17
now you can compute the left side
deep mural
oh and then i can take mod 17
because 10^23 mod 17 is 5
i think
so 10^j = 10 mod 17
and now it's easy
hard atlas
well j=1 doesnt work
deep mural
OH right j > 2
but still easy, I didn't even notice it lol
I was looking for powers that satisfy this and it seems to be j=20
wait no
17
is this the correct answer
hard atlas
yes
vocal sleetBOT
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Available help channel!
unique sluice
im not picturing this well enough
vocal sleetBOT
im not picturing this well enough
unique sluice
i dont understand
unique sluice
hallow plover
Eh... not quite
unique sluice
hallow plover
Getting warmer
hallow plover
Why do you assume that e^x grows to infinity before reaching 1
unique sluice
unique sluice
y do we say it starts at one? is that what e = when x is 0?
hallow plover
Now we also know that this shape has a square cross section in the direction of the x axis at all points
this is a bit difficult to visualize
unique sluice
unit 8 is on the ap calc ab exam?
unique sluice
Now we also know that this shape has a square cross section in the direction of ...
yes
hallow plover
Well you don't really have to visualize it at all
you just have to calculate it I guess
let's look at one of the cross sections
what's the area of that cross section?
for some x
Think of this a series of squares that get progressively larger
by the rule of e^x
the sum of the areas of these squares will give you the volume essentially
assuming they're infinetly thin
unique sluice
hmmm, well it would be x^2 where x would change as the x value grows, so
x^2 is equation for cross section
unique sluice
since the length of a side is e^x
waitm how do we know this
hallow plover
Yes we do
See the purple square
Emm.. "square", don't mind my art skills
it's located at 0.5
but it goes up to the graph of e^x
unique sluice
yes yes
hallow plover
so it has height e^x
and since it's a square
it also has width e^x
so it has surface e^x squared
now since we have a series of surfaces and we need to sum em together to get a volume
assuming they're infinitely thin, that is, dx thin
we have element volumes (e^x)^2 * dx
so if we integrate then in the bounds of 0 to 1
we will get the value of the volume
unique sluice
mate
hallow plover
ye?
hallow plover
Okay so the surface is e^x squared
because the shape of e^x
determines the height of the square at each cross section
and since squares have equal sides the width must also be e^x in that case
Each square goes from the x axis to the graph
unique sluice
but it tell us that y = e^x
btu now we are setting volume to (e^x)^2
hallow plover
Well we need to find the volume of the shape right?
And we know that the shape is made up of a series of squares
since the cross sections are all squares in the x direction
so let's slice up this volume into those infintely thin slices of squares
unique sluice
ok ok
hallow plover
the volume will be the sum, that is the integral, of the surfaces of those squares multiplied by their individual thickness
since they are infinetly thin that thickness is dx
unique sluice
alr
hallow plover
Are you sure you understand?
I could pull out some more graphics
So let's look at some cross section of the shape in the x direction
it's height is e^x
which means it's sides are e^x since it's a square, assuming the squares aren't twisted in some way
so the surface of that cross section is e^x * e^x
and the thickness, being infinitely thin, is dx, because that's what we do when we deal with infinite thin things
so the volume of this cross section segment is therefore
e^x * e^x * dx
or
(e^x)^2 dx
This is basically the elementary volume of some cross section
since this holds true for all cross sections of the shape
the total volume of the shape will be the integral of these parts
that is
the integral of (e^x)^2 dx
in the bounds of x
which are from 0 to 1
so solving this integral gives us the volume of the shape
vocal sleetBOT
@unique sluice Has your question been resolved?
quasi cosmos
Plz someone good at physics
vocal sleetBOT
Plz someone good at physics
noble comet
hmm
noble comet
I don't understand the (61)
It just follows from that, do you know how to set up the integral
quasi cosmos
not really
noble comet
I assume you have a cylindrical magnet moving across some surface
quasi cosmos
nah it's rotating
noble comet
Oh so you rotate a cylindrical magnet over a conductive plane
quasi cosmos
approximately yes
noble comet
Recall that your flux is BA*cos(theta)
where theta is the angle between the plane normal and the b field
noble comet
you sure you understand?
quasi cosmos
And isn't (62) inhomogenous ?
and about this ?
quasi cosmos
you sure you understand?
pretty
noble comet
Ok
The second one is just massaging some formulas
You already have your U
From 61
quasi cosmos
yeah ?
noble comet
you just plug it in and that's it
quasi cosmos
but why would it be R.U² instead of U²/R ?
noble comet
but why would it be R.U² instead of U²/R ?
because P = U*I
quasi cosmos
but I = U/R and not U.R
quasi cosmos
that's what i thought, but it seems weird as the paper is serious
noble comet
mistakes happen everywhere
quasi cosmos
Because it is supposed to be U^2/R
yeah i thought so
noble comet
I'm also doing edyn right now so I'm not that good yet
but I'm pretty sure it's a mistake
noble comet
$$ \Phi = \iint_S B \cdot dS $$
twin meteorBOT
dindu
quasi cosmos
ok, but how do we know that B is independent from \vec S ?
noble comet
intuitively you're just projecting the b field to the normal vector of the surface and adding those up
I don't have a sketch unfortunately but try sketching it out
noble comet
ok, but how do we know that B is independent from \vec S ?
No your b is already given
You're just trying to figure out how many field lines pass thru S
noble comet
but B depends from coordinates
yeah it does
B \cdot dS is just the flux at an infinitesimal area
noble comet
The flux overall is gonna depend on the bounds of your integration
quasi cosmos
B \cdot dS is just the flux at an infinitesimal area
yeah i'm ok with this
but as B isn't constant with respect to S, one can't just say \Phi = B.A.cos(\theta) right ?
noble comet
but as B isn't constant with respect to S, one can't just say \Phi = B.A.cos(\th...
Yeah but it's important to know where that comes from
noble comet
but as B isn't constant with respect to S, one can't just say \Phi = B.A.cos(\th...
This only works in a homogeneous magnetic field
noble comet
This only works in a homogeneous magnetic field
Ignore what I said, I was thinking of something else
You're correct lol
But it's good to keep the integral in mind
noble comet
but as B isn't constant with respect to S, one can't just say \Phi = B.A.cos(\th...
If your angle is changing with respect to time then it's just gonna be \Phi = B.A.cos(\omega.t)
noble comet
nah it is constant in time, but not in space
That's what that means
Since your magnet is rotating, the field lines are gonna rotate with it as well
quasi cosmos
but wouldn't it remain constant if we have a revolution symmetry axis ?
noble comet
but wouldn't it remain constant if we have a revolution symmetry axis ?
No, the flux would be changing with respect to time
B field would still have the same components but the angle between it and the surface would change with time
quasi cosmos
i'm not sure to understand
if the magnetic moment is normal to the surface, and the axis of symmetry is colinear to the moment
why would its orientation change ?
noble comet
quasi cosmos
but that's when all vectors of B are colinear, which isn't the case of a magnetic field produced by a magnet
noble comet
but that's when all vectors of B are colinear, which isn't the case of a magneti...
Yeah but even if they're not colinear they flux is gonna change if you change the angle
Infinitesimally taken the field lines are straight, I think
So this is just illustrating what happens in an infinitesimal element of area
quasi cosmos
but if here the magnet rotates around the South-North axis, why would the flux change ?
(the surface being the black line)
noble comet
but if here the magnet rotates around the South-North axis, why would the flux c...
Oh yeah then it wouldn't change
I think I'm just missing something
quasi cosmos
¯_(ツ)_/¯
quasi cosmos
i mean, i'm probably wrong, but i don't see why
noble comet
i mean, i'm probably wrong, but i don't see why
Yeah me neither
I think I know what we're missing
The concept of Faraday's Law is that any change in the magnetic environment of a coil of wire will cause a voltage (emf) to be "induced" in the coil. No matter how the change is produced, the voltage will be generated. The change could be produced by changing the magnetic field strength, moving a magnet toward or away from the coil, moving the coil into or out of the magnetic field, rotating the coil relative to the magnet, etc.
It's basically what I said, you just have to imagine the magnet spinning in the N-S axis in 3D
quasi cosmos
oh ok
noble comet
I'm still pretty skeptical but it sounds more right lol
quasi cosmos
now i understand why the flux change, but i'm not convinced about the way to calculate it
quasi cosmos
I'm still pretty skeptical but it sounds more right lol
yeah same
quasi cosmos
I don't understand the (61)
and even if it was B.A.cos(theta), I don't get where the 2r/v comes from, and his simplification then
noble comet
and even if it was B.A.cos(theta), I don't get where the 2r/v comes from, and hi...
Yeah this derivation kinda sucks
I think we're gonna have to get someone more experienced, not sure
noble comet
and even if it was B.A.cos(theta), I don't get where the 2r/v comes from, and hi...
2r/v is the period I think?
quasi cosmos
oh yeah im stupid lol
quasi cosmos
lmao
noble comet
there's a pi in the up part, why wouldn't it cancel
Well that'd give you the periodic flux
I guess?
quasi cosmos
weird
noble comet
Idk I'd just do this with the dipole approximation
$$ B = \frac{\mu_0}{4 \pi} \cdot \frac{2M}{r^3} $$
M is the magnetic moment in this case
r is the distance along the axis from the center of the magnet
¯_(ツ)_/¯
quasi cosmos
and M would be the inducted moment ?
noble comet
Yeah
twin meteorBOT
dindu
noble comet
Whoops missed a 2
quasi cosmos
ok makes sense, but why would M depend from S tho
quasi cosmos
ok
i'll see it tomorrow in the morning before i get to make my presentation
gotta sleep, it's nearly 2am ;-;
noble comet
nice
quasi cosmos
u ?
quasi cosmos
oh ok :)
quasi cosmos
ye but it looks so cool
noble comet
true
quasi cosmos
i haven't started the class about it tho
noble comet
You're also in physics?
quasi cosmos
huh
noble comet
Are you also a physics student?
quasi cosmos
I'm in a math-physics study curriculum
noble comet
uni?
quasi cosmos
(i don't know if that's how it says i'm shit at english)
quasi cosmos
uni?
no, it's called "prépa", it's preparation for the great schools of engeneering and research
quasi cosmos
goes well ?
noble comet
goes well ?
No
quasi cosmos
😬
noble comet
half the time I want to jump out of my window but it's worth it because physics is cool
It's extra hard because im lazy
and dumb
noble comet
yeah thanks I'm not at all surprised that Boltzmann killed himself
statistical mechanics is ass
Well gn and good luck with the presentation!
quasi cosmos
thanks :)
vocal sleetBOT
@quasi cosmos Has your question been resolved?
daring marsh
vocal sleetBOT
daring marsh
How do I find y intercept?
I think I can graph
I am not sure if the degree is correct though
terse rune
f(0) will give you the y-intercept
daring marsh
okay I see
so 4
I forgot what -2 does in the function
,rotate
Okay so how do I get degree and leading term those turned out to be wrong
,rotate
twin meteorBOT
vocal sleetBOT
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Available help channel!
fresh tide
vocal sleetBOT
fresh tide
where did the *1/x come from?
I understand u use the power rule which gives us 2[lnx] but how is 1/x part of that
lime gorge
Derivative of lnx is 1/x
fresh tide
yea but why add that
vocal sleetBOT
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charred axle
Hey, i was wondering if someone could help me with linear combinations
charred axle
This is what it is
I got
This as I made u, v and w as the m, n and p
I'm not sure or well I'm lost how to look for m, n and p now
vocal sleetBOT
@charred axle Has your question been resolved?
pallid forge
,rotate
twin meteorBOT
fast warren
Yes
fast warren
Well if u simplify it
sharp frost
Why is it 3x^3?
fast warren
It's wrong
fast warren
**kisnar**
Do same with this
sharp frost
$\frac{3x^2}{2}-cos x$
twin meteorBOT
Monarch of Eternal Night
sharp frost
Suppose
It's, (ax+b)^n
If you integrate
It'll be
$\frac{(ax+b)^{n+1}}{a.(n+1)}$
twin meteorBOT
Monarch of Eternal Night
twin meteorBOT
Monarch of Eternal Night
sharp frost
@vast shale
twin meteorBOT
kisnar
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rugged orchid
im struggling a bit to see why it's just ∑
vocal sleetBOT
im struggling a bit to see why it's just ∑
rugged orchid
why isn't it ∑^-1
if i define an inner product on R^n via a positive definite matrix A, then a circle wrt this induced norm would be x'Ax = r
if i imagine having a circle in 2D and applying a (diagonalisable) linear transformation on this 2D space, im sort of squeezing my circle
the 2 opposing points that i push in would be 1 of the eigenvector directions
and orthogonal to that would be the other eigenvector direction
aren't those precisely the eigenvector directions of A?
but here it's got A^-1 (well it starts with ∑ then has ∑^-1 at the end)
vocal sleetBOT
@rugged orchid Has your question been resolved?
tidal root
how do i do these types of questions
vocal sleetBOT
how do i do these types of questions
mellow oyster
a function f is continuous at a point a if f(a) is the same as the limit as f approaches a
for 1, your function is undefined at x = -2 since that would cause division by 0, so f(-2) doesn't exist, and if a function doesn't take on a value at a point, it can't be continous at that point
you run into the same problem for 2
actually this doesn't look like it's for a calculus class so pretend that i didn't mention limits
at this level, to show that a function is continuous at a point, just plug in the point and see if your function is defined
and to show that a function is continuous on an interval, show that either there are no points in that interval for whcih the function is undefined, or find some point in the interval where the function would be undefined
for example, f(x) = sqrt(1-x^2) would be undefined when the expression inside the square root is negative, ie when 1 - x^2 < 0
notice that no x satisfying that inequality are contained in your interval [-1, 1], so for the purposes of this class, that function is defined and continuous on that interval
vocal sleetBOT
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vocal sleetBOT
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cedar linden
Hi, there is something i dont have totally clear
vocal sleetBOT
Hi, there is something i dont have totally clear
cedar linden
\begin{flalign*}
2) \int \frac{x^2 - 1}{x^3 + x} &= \int \frac{x^2 - 1}{x(x^2 + 1)} && \\\\
x^2 - 1&= \frac{A}{x} + \frac{B}{(x^2 + 1)} \\\\
x^2 - 1 &= \frac{\cancel{x}(x^2 + 1)A}{\cancel{x}} + \frac{x\cancel{(x^2 + 1)}B}{\cancel{(x^2 + 1)}} \\
x^2 - 1 &= A(x^2 + 1) + B(x) \\\\
x &= 0 \quad \Rightarrow \quad A = - 1 \\
x &= 1 \quad \Rightarrow \quad B = 2 \\
&= \int \frac{-1}{x} + \frac{2}{x^2 + 1} \\
\end{flalign*}```Juan
cedar linden
i should have 2x instead of just 2 in the last line
so, what i am missing?
if it should be Bx instead of just B let me know why
inner osprey
if it should be Bx instead of just B let me know why
you you have Bx + C there but it turns out that C is 0
cedar linden
you you have Bx + C there but it turns out that C is 0
so i did everything wrong since first steps
ohh because you can convert
inner osprey
to decompose (something)/(x + 1)^2, use A/(x + 1) + B/(x + 1)^2
to decompose (something)/(x^2 + 1), use (Ax + B)/(x^2 + 1)
inner osprey
no this is just identifying decomposition
vocal sleetBOT
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pliant socket
Heyy! Same question went unanswered yesterday... I got part 1 and 3 fine but my part 2 answer does not work out with the given answer (I got 9/16, the answer was 17/32)
vocal sleetBOT
Heyy! Same question went unanswered yesterday... I got part 1 and 3 fine but my ...
pliant socket
No working out with me, it's a graph question anyway, if you want to feel free to graph it on desmos (I did eventually and still got the same answer)
vocal sleetBOT
@pliant socket Has your question been resolved?
vocal sleetBOT
@pliant socket Has your question been resolved?
vocal sleetBOT
@pliant socket Has your question been resolved?
vocal sleetBOT
@pliant socket Has your question been resolved?
vocal sleetBOT
vocal sleetBOT
Available help channel!
noble pendant
can someone give me a function which:
- is Continuous everwhere expect for x=0
- is Continuous everwhere expect for in Z
- is nowhere Continuous
- is only Continuous in Z
dawn holly
f(x) = \begin{cases}
x^2 & x \neq 0 \
1 & x = 0
\end{cases}
noble pendant
i meant i needed 1 function for every number
inner osprey
can someone give me a function which:
1) is Continuous everwhere expect for x=...
- see multiplicative inverse function
- see floor function
- see dirichlet function
- see
noble pendant
legend🙌
daring marsh
vocal sleetBOT
daring marsh
I know how to draw the point but not the lines
daring marsh
um idk
minor light
Try graphing it in desmos
