ye ok imma just send her a message
#help-13
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inner dawn
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You can use the bots in #bots. If you need a channel to get help with a math problem, see #❓how-to-get-help.
trail dune
Does this make sense or do I not know what inverse functions do?
twilit bison
i don't think that's the way they want you to solve it
trail dune
i don't think that's the way they want you to solve it
Yeah true, but was my initial idea correct?
That's how inverse functions work ye?
Get back da OG angle
twilit bison
it should work, yeah
trail dune
.solved
cedar kilnBOT
trail dune
ty
twilit bison
you'll need a calculator though
by the way
you need to make sure you put the angle in the right quadrant when you use inverse sin
hollow trail
you'd need to use a calculator to find x, but you don't need one to find sin(x/2), cos(x/2), and tan(x/2)
cedar kilnBOT
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trail dune
.reopen
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trail dune
How does this make sense? It feels like we just completely disregard it as being an inverse n just stick a theta symbol on it n tell da inverse to kick rocks
solemn quail
Ask yourself what cos inverse of x is really saying
trail dune
Ask yourself what cos inverse of x is really saying
This huh
soft holly
How does this make sense? It feels like we just completely disregard it as being...
If $\sin(2 \arccos(x)) = \sin(2\theta)$, then $2 \arccos(x) = 2 \theta$.
wraith daggerBOT
King Leo
trail dune
No, not that part. Just the concept of cos inverse of x
I can just look at it as a placeholder for the angle then yeah?
soft holly
I can just look at it as a placeholder for the angle then yeah?
$\theta$ is the placeholder for an angle.
wraith daggerBOT
King Leo
solemn quail
Yes, it's referring to an sable with a specific property
trail dune
I know but like
soft holly
No, not that part. Just the concept of cos inverse of x
@trail dune explain the arccos function in english (i believe this is what silkster is looking for)
trail dune
<@464205600474005519> explain the `arccos` function in english (i believe this i...
We extracting the angle back from the given values no?
soft holly
We extracting the angle back from the given values no?
What do the given values (in this case, x) represent
trail dune
The value of cos right?
soft holly
The value of cos right?
Explain in english. Idk what cos means (i do, but its important for you to understand how to describe arccos)
trail dune
We can find the angle that was used to find the adjacent/hypotenuse ratio
soft holly
Perfect
soft holly
We can find the angle that was used to find the adjacent/hypotenuse ratio
Now that you have that angle, youre plugging it into sin.
Can you explain sin in english?
soft holly
But I see it now
?
trail dune
We get dat angle back apply it to sin2, n since it's double, we can apply da double angle formula
Is that correct?
ty for the help bro
.solved
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novel veldt
The question is to find the gradient of the curve x=cos(2y) at x=0 (using the identity dy/dx = 1/(dx/dy))
novel veldt
This is the answer working out
I got dx/dy correct and the answer correct, but how did they achieve the second last step?
I dont see any similarity from the 4th to 5th step except for the 2's
hollow trail
they plugged in the equation they got for 2y into the derivative dx/dy
hollow trail
it results in -2 if k is even and +2 if k is odd
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urban otter
i got 7/20 but its wrong i need help
cedar kilnBOT
i got 7/20 but its wrong i need help
robust adder
why did you post the same problem here?
urban otter
why did you post the same problem here?
andrew told me to
buoyant python
why did you post the same problem here?
Bc i claimed the channel first
urban otter
oh wait nvm
sir do you know whos able to help?
robust adder
i can help
urban otter
im gonna be late for school
urban otter
i can help
ty sir
robust adder
so okay first
the question is asking in what probability do only one of the two will qualify, correct?
fallen heath
i got 7/20 but its wrong i need help
(Jack Qualifies) x (Charlie doesn't Qualify) + (Jack doesn't Qualify)(Charlie Qualifies)
urban otter
yes
fallen heath
Question asks that ✓
urban otter
(Jack Qualifies) x (Charlie doesn't Qualify) + (Jack doesn't Qualify)(Charlie Qu...
i got 7/20, it was incorrect though
robust adder
First the chance of Jack Quilifying is 3/10 but Charlie NOT qualifying is 1/8
So you multiply that to get ONLY Jack qualifying
3x1/8x10
fallen heath
Same context
robust adder
the chance of Grace qualifies is 7/10
robust adder
No
urban otter
ty guys
robust adder
np ?
cedar kilnBOT
@urban otter Has your question been resolved?
cosmic birch
cedar kilnBOT
cosmic birch
The answer will be a= (then idk)
cosmic birch
No I need help
swift olive
I suggest you to expand 3(2a + b) first
cosmic birch
6a+3b?
swift olive
correct
so you now have w = 6a+3b - 4
since, like you said, we want it to be a =, what do you think is the next step we should do
cosmic birch
+4 to each side?
cosmic birch
W+4=6a+3b
cosmic birch
-3b maybe?
cosmic birch
W+4-2b=6a
swift olive
Nice!
cosmic birch
*3b
swift olive
what do you think we should do next
cosmic birch
Divide by 6
cedar kilnBOT
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cedar bobcat
hey any body will help me in basics of parabola?
cedar kilnBOT
hey any body will help me in basics of parabola?
native heath
!da2a
cedar kilnBOT
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native heath
just ask lol
native heath
the bot said what i mean
native heath
maybe.
rough osprey
Like from the very basics?
rough osprey
You know quadratic equation right?
cedar bobcat
You know quadratic equation right?
yes
rough osprey
And you know the graph of the quadratic equation is forming a parabola
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plain granite
$x^2 + 3x = 7a - 12 - a^2$ find all values of a such that the equation's product of roots is equal to 0
plain granite
I have no idea how to start
wraith daggerBOT
asm
plain granite
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twilit escarp
<@&268886789983436800> lmao
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ionic bridge
Wtf
At first it looked like he was going to do some wwe move
Then i saw that thing
olive hedge
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cedar bobcat
And you know the graph of the quadratic equation is forming a parabola
yup
cedar bobcat
<@1316760432358326344> Has your question been resolved?
nopw
vestal bluff
resend your question
cedar bobcat
will u teach me basics of parabola?
vestal bluff
cant do that without a specific question
pastel vault
i mean just teach me the basic
cedar bobcat
https://www.khanacademy.org/math/algebra/x2f8bb11595b61c86:quadratic-functions-e...
thnk
blazing zephyr
x^2 -cosx ÷ sinx
could you send the original question?
cedar bobcat
this 1
pastel vault
this 1
this is unrelated to quadratics
this is related to the definition of trig functions
cos(x)/sin(x) = cot(x) by definition
pastel vault
nope v hve to solve by using function idk ?
there's no equals sign
cedar bobcat
shit
pastel vault
so you aren't solving anything
cedar bobcat
sry i hve send u the limits 1
find the coordinates of the focus, axis of the
parabola, the equation of the directrix and the length of the latus rectum
<@&286206848099549185>
cedar kilnBOT
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2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
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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
how do u k this ncert?
native heath
it's very clearly ncert lol
cedar bobcat
?
cedar kilnBOT
@cedar bobcat Has your question been resolved?
broken ice
could anyone help me find list of undefined math operation?
such as
division by 0, log(0), pow(0.0, 0.0), etc
just up to around bachelor university math
vestal bluff
im sure theres a wiki page somewhere
broken ice
I did find undefined math wiki, but I think the list is fairly not complete. maybe I open the wrong one?
like this one don't have log(0)
https://en.m.wikipedia.org/wiki/Undefined_(mathematics)
cedar kilnBOT
@broken ice Has your question been resolved?
split yarrow
could anyone help me find list of undefined math operation?
such as
division by...
Basically from what I remember from real analisis is that undefined just means that zero isn't the only answer. Eg 0/0 can also mean infinity at the same time.
cedar kilnBOT
@broken ice Has your question been resolved?
broken ice
alright thx all
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paper coral
I must aqquire helppp C:
cedar kilnBOT
I must aqquire helppp C:
paper coral
Similar values have been found for mussels on the seabed in the Arctic
the age of the mussel and the length of the mussel shell as shown in the table.
Mussel age (years)
Shell length (cm)
In one model, it is assumed that the length of the mussel shell as a function of the age of the mussel is one
function of the type
L(t)=b.tª,
where L is the length of the shell (measured in cm) and t is the age of the mussel (measured in years).
a) Use the data in the table to determine the numbers a and b.
b) Use the model to determine the length of the shell of a clam that is 24 years old
old.
c) Determine the number L'(24) and describe what the number tells about the growth of the clam shell.
the table thingy the upper line is mussel age in years the lower part is shell lenght in cms
Ive used the formular for finding a and b but im not sure if ive done it right?
i mean i picked the two first coordinates is that correct?
this is the results i got
i dont understand how to begin on b T_T
im using Maple if that helps
like as a math program
this is my question to task b) im guessing that i have to put it like this? L(t)=0,79*24^1,335 ?
would that be correct?
dies in confusiono
cedar kilnBOT
@paper coral Has your question been resolved?
cedar kilnBOT
@paper coral Has your question been resolved?
cedar kilnBOT
@paper coral Has your question been resolved?
swift olive
I think I can help you @paper coral
Just give me a sec
So we want to fit the data to the model L(t) = bt^a
paper coral
So we want to fit the data to the model L(t) = bt^a
ye i think i figured it, i atleast handed i hope so XD
ty for tryin tho idk how to close this
now
swift olive
Okay goodjob but just for comparison what I got is a = 0.654787 and b=1.2302
Almost the same as yours 👍
cedar kilnBOT
@paper coral Has your question been resolved?
sterile elm
Help
sterile elm
So let’s say u got a bottle of cologne and it’s 500$ for 200ml
And u have 50ml left
How much is it worth ?
grand arch
you can write a ratio
sterile elm
?
grand arch
like a fraction of dollars to ml
robust adder
$500/200ml = x/50ml
You can divide the numerator and the denominator by 4
To get the same denominator
125/50 = x/50
x = 125$
warm apex
Is there a formula to take 12 equally shaped sizes slices of a pizza?
warm apex
like i want 12 equally sized slices of pizzas
digital cliff
dont think you particularly need a formula
if you have a protractor or something just cut a new slice at 30 degrees from the previous (from the center)
assuming this pizza is a perfect circle anyway
cedar kilnBOT
@warm apex Has your question been resolved?
warm apex
dont think you particularly need a formula
if you have a protractor or something...
so we just use angle as a way of measurement?
oh that does make sense
ty
.close
winter tulip
Can I get an assist?
next iron
please help with this question of functions, the options are A) 4 B) 10 C) 11 D) 16
frigid dust
!status
cedar kilnBOT
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
i dont know where to begin
frigid dust
Try filling in whats given first
next iron
I tried replacing x with x/3 but it didnt seem to help
frigid dust
Try filling in f(8)
high bridge
think about this, how do you fit f(8) into the equation f(3x)-f(x)=x
next iron
uh, i will try
frigid dust
Basically, fill in x=8 into the equation
next iron
Basically, fill in x=8 into the equation
um..like this?
next iron
Why did you do the x/3 stuff?
It's actually given in the answer key, but I don't understand how it works
So I was looking for another approach to it
But couldn't think of any
frigid dust
f(3*8)-f(8)=8
Evaluate this
next iron
😭 I'm pretty sure I am more confused now
frigid dust
Questions like this are just a lot of trial and error
high bridge
I am not sure if this is trial and error
frigid dust
Going into paths that may lead to a dead end, but unknown until youre traced them
next iron
in the answer key they have replaced x --> x/3 infinite times
frigid dust
Unless you instantly see how to do it, its trial and error
frigid dust
in the answer key they have replaced x --> x/3 infinite times
To get to 0?
next iron
Hold on I'll send the answer
I'm not sure how I'm supposed to think like this in the actual exam
@frigid dust @high bridge
high bridge
hmm
I dont get why replacing the x value with x/3 infinitely will result in the first term being just f(x)
frigid dust
Its getting a new equation, and then plugging it back in
If you want you can take y=x/3 and get the same result
next iron
If you want you can take y=x/3 and get the same result
nah the answer is completely different
next iron
please help with this question of functions, the options are A) 4 B) 10 C) 11 D)...
<@&286206848099549185> if anyone can explain the answer key or has an completely different approach, kindly help
next iron
Can be called anything
i can be, but that way f(0) = -1
frigid dust
f(3x)-f(x)=x
f(x)-f(x/3)=x/3
f(3x)-(x/3+f(x/3))=x
f(3x)-f(x/3)=4x/3
This is the solution btw, just repeated
next iron
and f(14) becomes 13
frigid dust
\begin{align*}f(x)-f(x/3)&=x/3\f(x/3)-f(x/9)&=x/9\f(x)-(f(x/9)+x/9)&=x/3\f(x)-f(x/9)&=x(1/3+1/9)\end{align*}
wraith daggerBOT
Bonk
frigid dust
Do you see whats happening?
next iron
Do you see whats happening?
i dont understand the 3rd step actually
frigid dust
From 2 to 3?
frigid dust
We rewrite line 2 as: f(x/3)=f(x/9)+x/9
Then we plug that back into the equation on line 1, to get to line 3
frigid dust
after the 4th line? what next
We repeat
frigid dust
Line 2 becomes x/9 and x/27
frigid dust
so basically replace x --> x/3 again?
Yup
next iron
alrighttt
frigid dust
So we get f(x)-f(x/27)=x(1/3+1/9+1/27)
next iron
So we get f(x)-f(x/27)=x(1/3+1/9+1/27)
wait, how many times do I actually do it?
time alloted for this question is just 3 minutes in the exam
frigid dust
Gl
next iron
.close
cedar kilnBOT
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solid cedar
Have I classified this algorithm correctly?
cedar kilnBOT
Have I classified this algorithm correctly?
cedar kilnBOT
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chilly forum
im not sure how to rearrange this, i got up to dy/dx (x) = y^2 but idk where to go from there
tight birch
this is separable
coral jewel
im not sure how to rearrange this, i got up to dy/dx (x) = y^2 but idk where to ...
pretend dy/dx is a fraction
arrange everything so that you have dy with only things with y on one side and dx with only things with x on the other side
obsidian crest
currently trying to learn functions for precalc and trying to find the domain of f(x)=1/x-3. i havent seen anything like this yet and dont really know what to do. thanks!
twilit bison
do you know the meaning of domain?
obsidian crest
its all possibilities of x?
crimson delta
1/x-3 or 1/(x-3) ?
twilit bison
yeah when the function is defined
obsidian crest
its 1 over x-3
twilit bison
the subtraction isn't going to be a problem but division is sometimes undefined
you can't divide by 0
obsidian crest
ah im kinda confused
i dont think i need to solve that equation
if i have -1=0.5x whats the proper way to factor?
obsidian crest
wait nvm i did it wrong
twilit bison
the range will be everything except when the denominator is zero
twilit bison
this is a different problem
obsidian crest
yeah i was doing one i wasnt supposed to
prisma pike
g(2) just means the value of the function at x=2
obsidian crest
oh wow dang i was trying to find the equation
twilit bison
you can just read the graph
prisma pike
So g(2)=?
obsidian crest
4
prisma pike
You’re finding the x such that the value of the function is 2
obsidian crest
is it -3?
prisma pike
Yeps
obsidian crest
so if its f(x)= 3 its on the x axis?
prisma pike
Well not how'd I'd phrase it but yes ig
obsidian crest
i dont really understand whats goin on on these graphs, we literally just went over what a function is
im suppossed to find f(-2) f(-1) f(0) f(1) f(2) of f(x)=8x^2-7x+3
i did them all individually just wondering if theres a faster way than just doing them all one at a time
inner solar
how to dedtermine absolute convergence of this series
cedar kilnBOT
how to dedtermine absolute convergence of this series
kindred elm
convert sinh to tanh
cedar kilnBOT
@inner solar Has your question been resolved?
inner solar
but these are identities for arctan not tanh arent they?
kindred elm
ohh mb i confused it
forest socket
the original exponent is n-3
i need exponent to be (n-2)/4
i dont know how to do it
cedar kilnBOT
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rare grail
cedar kilnBOT
rare grail
Do how you do these 2 question?
upper laurel
Do how you do these 2 question?
do you know about the identity sin(2x) = 2 sin(x) cos(x)?
rare grail
do you know about the identity sin(2x) = 2 sin(x) cos(x)?
Uh no ●_●
rare grail
do you know about the identity sin(2x) = 2 sin(x) cos(x)?
I can search it on Google rn tho
upper laurel
I can search it on Google rn tho
an identity is an equation that is always true for all x
for example 2x + 2 = 2(x + 1) could be an identity
you can use that here
instead of asking "find the value of sin(2x)"
you can ask "find the value of 2 sin(x) cos(x)"
and its guaranteed that sin(2x) and 2 sin(x) cos(x) are essentially the same thing
identities are figured out, but figuring them out I dont think is necessary for your problem? I am not sure though
rare grail
identities are figured out, but figuring them out I dont think is necessary for ...
●_● for me I js have a problem for tan sin and cos cus I barely know it
upper laurel
in that case we can take things one step at a time
first, with tan(x) = 4,
you know tan represents a ratio on a triangle, right?
rare grail
you know tan represents a ratio on a triangle, right?
Opposite / adjacent
upper laurel
now we can draw a triangle that represents this
you can think of a triangle with opposite side = 4 and adjacent side = 1
this would be a triangle where tan(x) = 4, right?
rare grail
Ye
Oh and by a² + b² = c² we can find out the hypotenuse
Hm ●_● doesn't that mean it's square root of 17
upper laurel
Hm ●_● doesn't that mean it's square root of 17
it will come out right in the end
now from here, we need twice of the original angle
to think about this, notice something interesting about the ratio opposite / adjacent
upper laurel
this would be a triangle where tan(x) = 4, right?
if you doubled all the sides of the triangle (if the triangle is twice as big), would its tan(x) change?
rare grail
Oh no it wouldn't
upper laurel
that means if you scale all the sides of the triangle by the same amount, would its tan(x) change?
upper laurel
So we should increase it until the hypotenuse becomes an interger?
well thats not possible since √17 is irrational
but we have a way to work around this
think of drawing the triangle on grid paper
your triangle's diagonal would go from (0,0) to (1,4), right?
rare grail
Yea
upper laurel
now if we want to draw the same angle, we would need another triangle with the same shape
that would mean the opposite side is 4 times longer than the adjacent side
(and is at a right angle to the adjacent side)
upper laurel
So we are going to make a square?
no
commonly, a square has all of its sides be the same
however I am asking you to make something else
rare grail
(and is at a right angle to the adjacent side)
Oh so you mean make another triangle but just flip it over?
upper laurel
do you have grid paper with you?
upper laurel
do they allow you grid paper on the test?
rare grail
do they allow you grid paper on the test?
Yea
upper laurel
then you need to have grid paper with you
this is what it is for
this time I will show you what it looks like on a grid
rare grail
👍👍
upper laurel
here is what the original triangle looks like, right?
rare grail
ye
upper laurel
now take a look at this length
now notice that I am drawing this line from (1,4) to (-3,5)
you can see it looks like the same sort of length but rotated 90 degrees, right?
rare grail
ye
upper laurel
so can you trust that this new green line is 4x longer than the original (1,4) red line?
rare grail
uhhhh idk ._.
upper laurel
take a look at it this way
I made the green line by starting at the red point (1,4) then going 4 left, 1 up
compare that to the red line, which was formed by going 1 right, 4 up
if you think about it, these two directions must be at 90 degrees to each other
do you see why?
rare grail
do you see why?
cus u can make the edge like a square?
upper laurel
its more of that the green triangle is a 90-degree rotation of the red one
rare grail
its more of that the green triangle is a 90-degree rotation of the red one
yea but what can we do with that info?
upper laurel
here's the original green length
now if I make the green length 4x longer, it would now look like this
you can see all I did was copy-paste the same "4 left, 1 up" kind of line
rare grail
oh ok but now what?
upper laurel
now consider this triangle
notice that this triangle has the side from (0,0) to (1,4)
and the longer side that we talked about
upper laurel
if you think about it, these two directions must be at 90 degrees to each other
now we already drew this side at a right angle
upper laurel
now if I make the green length 4x longer, it would now look like this
then we made that side 4x longer
upper laurel
now consider this triangle
that is where this triangle came from
so does it make sense that the opposite / adjacent for the green triangle is 4?
pastel vault
cus its js 16/4 right?
yes
by similar triangles you can use the ratio of the horizontal distance of opp (16) and the vertical distance (4) of adj
rare grail
So how do we calculate the awnser
I already know the awnser is 8/17
Cus I got the awnser sheet
But I'm js want to know how
upper laurel
cus its js 16/4 right?
its sort of like 16/4, but really its 4√17 / √17
remember that original side from (0,0) to (1,4) isnt 4
now whats important about the red and green triangle is around here
we've established that both of the triangles have the same tan(x)
so does it make sense that the same angle x would be in both triangles?
rare grail
Ye
upper laurel
now sin(2x) = sin(180 - 2x), right?
rare grail
Ye
upper laurel
now take a look at this triangle
then, this angle
we have x = the red angle
2x = red angle + green angle
then 180 - 2x is?
upper laurel
@rare grail 180 - 2x is the white angle
upper laurel
@rare grail the angle that is part of the white triangle
rare grail
<@1060886328843186238> the angle that is part of the white triangle
Uhh 28.07? If ur talking about like the theta of the while triangle
rare grail
Ye
upper laurel
sin(180 - 2x) = 8/17
and sin(2x) = sin(180 - 2x)
so sin(2x) = 8/17 too
so you figure out now that sin(2x) = 8/17 by drawing a version of 2x then sketching its sine
upper laurel
np
rare grail
.close
vestal sandal
Can someone prove associativity for Zn brev
cedar kilnBOT
Can someone prove associativity for Zn brev
upper laurel
Can someone prove associativity for Zn brev
you can use this definition to get a "formula" for adding two residues together
so for example 2 + 3 would be the first or second line except with (2 + 3) for k
using this, you can show (a + b) + c = a + (b + c) by just having those appear in for k in the definition, then using the integers's associativity axiom
cedar kilnBOT
@vestal sandal Has your question been resolved?
vestal sandal
Are you saying something like this
Could you please explain further @upper laurel
upper laurel
a bar = {x in Z | x - a = 0 (mod n)}
b bar = {x in Z | x - b = 0 (mod n)}
a bar + b bar = {x in Z | x - (a + b) = 0 (mod n)}
vestal sandal
isn't the first condition only true for something that is completely divisible
like 6 mod 2 is 0
n times a
where a is 0
how do we know any a or any b is completely divisible or not
and isnt k the remainder itself
cedar kilnBOT
vestal sandal
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cloud creek
We can construct a sequence of integers by adding to each number twice the sum of the digits that compose it. For example, starting from 1000, we obtain:
1000 + 2(1+ 0 + 0 + 0) = 1002;
1002 + 2(1+ 0 + 0 + 2) = 1008;
1008 + 2(1+ 0 + 0 + 8) = 1026;
and so on.
How many starting numbers strictly lower than 2025 make it possible to reach the number 2025?
cloud creek
wdym
sly swan
i have no idea wtf this sequence is
sly swan
yes
sly swan
yes
native heath
id write code honestly
cloud creek
so therefore
cloud creek
~~id write code honestly~~
i thought about it
cloud creek
well it's def not any of the even numbers
how
native heath
i thought about it
you sure this isnt a coding question lol
cloud creek
oh wait yeah
native heath
okay then ill think about it lol
sly swan
whats the next number
sly swan
1026 + 2(1 + 0 + 2 + 6)
cloud creek
1026 + 2(1 + 0 + 2 + 6)
right
sly swan
we are adding 18
cloud creek
yeah
sly swan
1044 + 2(9)
why are we adding 18
I feel like we just constantly keep adding 18
then it becomes 36
then 18
18 18 36
funny pattern
cloud creek
we have to like add a limit of numbers to test
quartz coral
We can construct a sequence of integers by adding to each number twice the sum o...
x' = x + 2 * S(x), where S(x) is the sum of the digits of x
Suppose x' = 2025
x = 2025 - 2 * S(x)
The numbers need to be in this exact form.
the process onward is just trial and error and testing each number
which sucks
cloud creek
@native heath
cloud creek
x' = x + 2 * S(x), where S(x) is the sum of the digits of x
Suppose x' = 2025
...
lol ik
but you can set limits
quartz coral
yes
cloud creek
in the sense test numbers that could theroitacaly work like from suppose 1900-2025
cuz suppose below 1900 it possibily wouldnt get 2025
making the trial and error easier
also factoring out even numbers
but
I made a code in python
def sequence(num):
num_str = str(num)
digit_sum = 0
for digit in num_str:
digit_sum += int(digit)
result = num + digit_sum * 2
return result
count = 0
for num in range(1, 2025):
if sequence(num) == 2025:
count += 1
print(count)
it gives me 4 as the answer
but ima have to proof check that
vivid tundra
that only does the operation once though
cloud creek
that only does the operation once though
wdym
vivid tundra
it does the x' = x + 2Sum(x) once
in the original question you can do it more than once
cloud creek
it does the x' = x + 2Sum(x) once
are you talking about the code?
vivid tundra
yea
cloud creek
so how could i fix it
quartz coral
it needs to be in loop till 2025
vivid tundra
you need to apply sequence over and over again until it reaches 2025 or surpasses it
cloud creek
im blanking can u like input the needed improvemnts in the code
like form my message
quartz coral
you need to make a while loop
so it loops over and over
till it reaches the value
of 2025
cloud creek
def sequence(num):
num_str = str(num)
digit_sum = 0
for digit in num_str:
digit_sum += int(digit)
result = num + digit_sum * 2
return result
count = 0
for num in range(1, 2025):
if sequence(num) == 2025:
count += 1
print (num)
print(count)
so like i make the while loop
uh
native heath
this is still not right i think
cloud creek
wait
def sequence(num):
num_str = str(num)
digit_sum = 0
for digit in num_str:
digit_sum += int(digit)
result = num + digit_sum * 2
return result
count = 0
for num in range(1, 2025):
current_num = num
while current_num < 2025:
current_num = sequence(current_num)
if current_num == 2025:
count += 1
print(num)
break
print(count)
i think it makes sense now
i got 48 as a new answer
cloud creek
1847
1849
1853
1855
1859
1861
1865
1867
1871
1873
1879
1885
1887
1889
1891
1893
1895
1903
1905
1907
1911
1913
1919
1925
1927
1929
1931
1933
1935
1937
1939
1941
1943
1945
1951
1957
1959
1963
1965
1967
1971
1973
1977
1983
2001
2003
2007
2013
native heath
love bruteforce
vivid tundra
same, it's great
cloud creek
wait just to clarify bruteforece as in trial and error right?
vivid tundra
checking every possible number, yea
vivid tundra
just did it in desmos
basically
n = [0...2024]
n -> n+2*s(n)
then count how many there were reached 2025
cloud creek
wait no there is an error
cloud creek
1847
1849
1853
1855
1859
1861
1865
1867
1871
1873
1879
1885
1887
1889
1891
1893
...
how does 1847 give 2025
vivid tundra
,calc 2007 + 2*(2+0+0+7)
cloud creek
but ur saying u got 48 too
wraith daggerBOT
Result:
2025
there it reached
vivid tundra
but ur saying u got 48 too
48 total numbers, yea
vivid tundra
it does?
why doesn't it work?
vivid tundra
,calc 1847 + 2*(1+8+4+7)
wraith daggerBOT
Result:
1887
wdym
vivid tundra
that was your original question no?
cloud creek
no
vivid tundra
doing the operation until you get 2025
vivid tundra
We can construct a sequence of integers by adding to each number twice the sum o...
you did it over and over here
but if you mean just do the operation once, then it becomes much easier
cedar kilnBOT
@cloud creek Has your question been resolved?
cedar kilnBOT
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eternal pollen
Is this the correct way to tackle this problem?
cedar kilnBOT
Is this the correct way to tackle this problem?
eternal pollen
eternal pollen
It was more to see that I wasn't making a mistake
twilit escarp
you did not
eternal pollen
But that would be an acceptable way of showing how I found c on an exam?
twilit escarp
to me yes but depends teachers so that's why its better to use delta = 0 cuz its probably how they want you to do
eternal pollen
Fair
But thank you
Oh another problem
How do I "show" that the graph of P(x) = x³ + x on crosses the x axis once?
Like properly
Because this feels like a dumb way of doing it
Especially the +x part
.close
cedar kilnBOT
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weary lintel
In a paper of English there are 5 questions such that the sum of marks is 30 and the marks for any question is not less than 2 and not more than 8. If the number of ways in which marks can be awards is a 3 digit number xyz then value of (x+y+z) is
weary lintel
i tried solving with princle of inclusion and exclusion but wasnt getting any furthur
dusk finch
I'd try subtracting one from each mark
weary lintel
can you elaborate
first what i did is satisfy the lower condition of marks greater than 2
dusk finch
can you elaborate
I mean like instead of working with the marks itself, works with the marks - 1. That way the bounds will become 1 <= mark - 1 <= 7, and the "mark - 1"s will sum to 25
the motivation behind this is having better bounds to work with
weary lintel
let me try
dusk finch
does it want the sums?
wdym?
fair geyser
oh it sums to 30 i get it
dusk finch
It's basically ⭐ & 📊
weary lintel
basically it wants the total permutations of how we can distribute 30
fair geyser
i don't know how it's solved
weary lintel
I mean like instead of working with the marks itself, works with the marks - 1. ...
after doing this i am not getting a 3 digit number
dusk finch
after doing this i am not getting a 3 digit number
what did you get
fair geyser
usaullay there's only a few cases that are not allowed, and i can manually figure it out
dusk finch
hmm it shouldnt be that complicated
weary lintel
what did you get
19 * 18 * 34
weary lintel
usaullay there's only a few cases that are not allowed, and i can manually figur...
3 cases actually
when 1 question gets marks greater than 8, when 2 gets , when 3 gets
weary lintel
the lower bound condition is pretty easy to do it
dusk finch
ye
weary lintel
the main complication is the upper bound
fair geyser
maybe it should just be upside down
we can get 40, and we want 30
so there's 10 negative marks to distributte
yeah
dusk finch
combining inclusion exclusion with stars & bars also works
dusk finch
so there's 10 negative marks to distributte
what do you mean by this btw?
weary lintel
will using 3 additional dummy variables help?
like thats the no of questions which can get a max of 8
and then if i put the lower bound condition
fair geyser
the smallest amount is 10, and there's 20 marks that go anywhere to add up to 30
but also the highest amount is 40 and there's 10 marks that we can subtract
and 10 is less than 20 so maybe it's easy
but it's not by much
weary lintel
will multinomial theorm help
dusk finch
i got an answer by inclusion-exclusion
i will just brute force it to verify it in python
Yep, it's correct
weary lintel
what did you get
dusk finch
826
basically I shifted the marks down by 2, which means that im just trying to find solutions to
a1 + a2 + a3 + a4 + a5 = 20, where 0 <= ai < 7
so firstly we can ignore upper bound and directly apply ⭐ & 📊
that'll be 24 choose 4
fair geyser
yeah so my way is a bit easier
10 into 5 but 7+ is not allowed
3 into 5 = 35 wrong ways
times 5 for the choice of which one is 7+
1001 − 175 = 826
because 10 is less than 20, there's no way to get two variables out of bounds
fair geyser
that's the same thing probably
cedar kilnBOT
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Available help channel!
dusk pike
Isn't the lower quartile supposed to be 2.25th value and higher 6.75th values?
fallen heath
,rotateccw
wraith daggerBOT
cedar kilnBOT
@dusk pike Has your question been resolved?
cedar kilnBOT
@dusk pike Has your question been resolved?
crimson sedge
Isn't the lower quartile supposed to be 2.25th value and higher 6.75th values?
You are right, it should be that
cedar kilnBOT
@dusk pike Has your question been resolved?
dire heath
TRIGONOMETRY
I cannot find the value of x in the image.
cedar kilnBOT
# TRIGONOMETRY
I cannot find the value of x in the image.
uneven quartz
Lmao 'THEME'.
twilit bison
oh you can find similar triangles
dire heath
oh you can find similar triangles
how so?
uneven quartz
how
dire heath
yeah i see, but how do I like.. find TP?
twilit bison
we don't need to find TP
dire heath
is it like 17 - x?
dire heath
what would be the formula for it? since it's a obtuse triangle?
twilit bison
it doesn't matter if it's obtuse, we just set the ratios of sides equal
you can say RS/RP = RT/RS
dire heath
so basically, 10/17 = X/10 ?
twilit bison
Yes
dire heath
so, 100 = 17x, 17x = 100/17, x = 5.9 ? Like this?
twilit bison
Yes 5.9 is correct
cedar kilnBOT
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Available help channel!
outer jackal
hello I have a very quick question (vaguely related to series and limits):
if I want to show that some a(n) is bigger than another b(n) for n → ∞
is this enough proof, is it legit?:
lim(a - b) = ∞
→ a(n) > b(n) for n → ∞
concrete example:
ln(n) ≤ √n at n → ∞
because
lim(√n - ln(n)) = ∞
sorry for terrible notation I wrote this from my phone
any help is appreciated
outer jackal
if anyone replies pls ping me
dull oxide
hello I have a very quick question (vaguely related to series and limits):
if I...
you just want to prove lim(a-b)>0
outer jackal
is it legit
does it definitely prove that one is bigger than the other
@dull oxide
dull oxide
does it definitely prove that one is bigger than the other
!xy
cedar kilnBOT
does it definitely prove that one is bigger than the other
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.
outer jackal
!xy
I mean there's no problem that was given to me I was just thinking about this
but we can use the example:
prove that n^p > ln(n) as n → ∞ for any p > 0
sorry if the question is simple lol it's late in the night for me
dull oxide
I mean there's no problem that was given to me I was just thinking about this
bu...
This problem is kind of weird
there's some ambiguity to the way it is asked
outer jackal
how so
is it about the n → ∞
we can also say c ≤ n < ∞ where c is just some big number
sorry I'm not good at making math rigorous
dull oxide
Consider the two series $a_n=2^{-n}$ and $b_n=-a_n$. Every $a_n>b_n$, but they converge to $0$. Also, you could do $c_n=n+a_n$ and $d_n=n-a_n$, now, both series diverge, but still every $c_n>d_n$, and their difference converges to zero
wraith daggerBOT
SWR
outer jackal
🤔
thank you for taking the time to write this down but I don't see how it relates to what I asked
wait nevermind
I see how my question is inherently flawes
flawed*
thanks for the time
.close
cedar kilnBOT
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buoyant perch
i am so bad at python 😭 hopefully people can see what im trying to do with the loop but it just doesnt work at all, im wanting to work out the derived length of a group and i know i have to use a recursive function but i have literally never done that before any assistance would be appreciated
modern tide
Please ask math questions.
buoyant perch
is this not a math question?
the derived length is the number of times you have to take a commutator subgroup of a group G until it is the identity group and not all groups have a derived length
if im not meant to ask this here could i be directed to where i can ask it
crimson delta
is PermutationGroup(M) doing what you hope it does?
buoyant perch
i figured basic python is a part of maths so idk a single degree you do where you wouldnt be doing this
crimson delta
I would expect from the name that it gives you the group operating on the elements in the list
not the subgroup generated by those elements
but thats just guessing, havent checked the doc
buoyant perch
PermutationGroup(x,y) gives you the group x^i*y^j for arbitrary x and y
theres a better way of saying it
crimson delta
hmm
buoyant perch
but also derived length of S2 should be 1 but it always just gives me the highest number i put as the range -1
crimson delta
wait
the last two lines should be intended, no?
you are just running through the loop ten times and then generate Q once
buoyant perch
if i had
x = Permutation(1,2)
y = Permutation(2,3)
P = PermutationGroup(x,y) would just be S3
honest to god i have no idea how loops work that well but ill try to see if it should be indented
omg im so stupid
i knew it would be something like this
i just didnt indent Q = PermutationGroup(M) lmao
how do i stop a loop early btw
that should be something i know
crimson delta
break
buoyant perch
okay thank you
im glad i had the right idea and it was an indentation error i feel less stupid
.close
cedar kilnBOT
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Available help channel!
ember kindle
hi so uhm i need help with this question. ive tried multiple times with the steps provided on the video and it still says im incorrect , to the point i got fed up and used ai . i put in ai answers and its still wrong .
frigid dust
!status
cedar kilnBOT
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
3 and 1
frigid dust
what was your answer, and how did you get there
ember kindle
what was your answer, and how did you get there
there was a video attatched , and the question changes every 3 times i got it wrong so i have no data of any previous workings.
digital cliff
walk through how you might try to do this one
ember kindle
walk through how you might try to do this one
im srry i rlly dont know , i was never taught this either .
digital cliff
do you know the formula for the circumference of a circle?
frigid dust
do you know the formula for the area of a cylinder?
odd verge
Sniped twice
ember kindle
not rlly
maths isnt my strongest subject so im not rlly caught up to people in my class either
twilit bison
the area of the label will be its height times the circumference
twilit bison
it's like height times length but the length is wrapped around
ember kindle
does it say in the book?
what book?
frigid dust
do you not have a textbook you learn out of?
ember kindle
no?
frigid dust
where are you getting these questions from?
odd verge
You should get one
frigid dust
homework from who?
twilit bison
why does that matter?
frigid dust
the people that give the homework dont give explanations of how to do it?
ember kindle
homework from who?
my teacher
ember kindle
the people that give the homework dont give explanations of how to do it?
they just say " use the video attatched" and thats all they do
ember kindle
yeah i used the same calculations and everything but it still ays im wrong
glad peak
Did you make sure to give answer to 1 decimal place?
ember kindle
yes.
glad peak
And you did 100 * green area / total area?
ember kindle
And you did 100 * green area / total area?
ey
glad peak
And what were your calculations for the areas?
ember kindle
there was a video attatched , and the question changes every 3 times i got it wr...
. @glad peak
glad peak
Just replace the numbers with what you have now, I just need to see what formula you used
ember kindle
yes i have no data of ANY calculations ive done so i dont have ANYTHING right now but a blank answer
digital cliff
but do you have recollection of what formula you were using?
ember kindle
i check the video every time for that
glad peak
Did it look something like 2 * pi * 11 * 5?
ember kindle
ok
frigid dust
you need to know them by heart (not needing to have to look it up each time0
ember kindle
you need to know them by heart (not needing to have to look it up each time0
thats also kinda the reaosn why i reached out for help
twilit bison
do you know the formula for the circumference of a circle?
frigid dust
but you only need to look it up in the video once, then write it down right?
twilit bison
it's 2pi*r
ember kindle
do you know the formula for the circumference of a circle?
what does that have to do with the label tho
twilit bison
the label is like a rectangle wrapped around a circle
it has a height, and its width is the circumference
so the area is height * width or height * circumference
ember kindle
okay i take that back
i wanna ask
@twilit bison for part b
is it 38%
idk how to do part a , its not on the video anyway
odd verge
khanacademy
odd verge
khanacademy
Use this website
odd verge
Learn about surface area if the course is available
twilit bison
i think you'll need to do part a in order to do part b
ember kindle
that's not what i got
well i got 37.9 percent by following the calculations
on the video
twilit bison
would you like me to check your calculations?
ember kindle
Yes pls
first i did
2xpix24x5
i got 24 by adding 11 = 13 together
then i did pi r squared which gave 25pi
i added 240pi and 25 pi and 25 pi to get 290 pi .
thats 1 calculation done
then i did rx11x2 to get 110
then i did 110/290 to get 11/29 to get 37.9%
omds the multiplication marks
disappeared
twilit bison
try putting \ before *
ember kindle
ill just put an x