#help-10
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♡ PandaPanda2By4 ♡
so can you explain how this works again
do you mean sec?
♡ PandaPanda2By4 ♡
wouldn't the answer be 5?
what is the value of cos?
uhh
rn I did a graph that is
3, 1
right angle triangle btw
rn I'm finding the
sec theta =
cos is a/h
so, sec should be h/a
what's the h?
how is 5*5=10?
the a is 3 right?
ye
so, what would be sec theta?
yeah, and you should keep the sqrt(10) like sqrt(10) instead of computing it
yeah
what is the tan?
yeah, what's the value of the tan theta?
3/1
that's the cot
but sure, it's because 3/1 is equal to 3
and because your thing requires the simplified answer, the answer is 3
cos is h/a right?
oh, yeah, it is
cos is a/h=4/5
so, we can find the a, h, and o from that
the o, yeah
alr so it would be 20+25=55 and that's like sqrt 55 would be 7.416198487
alr got it
so sin would be sqrt(55)/5
ye?
that's the csc
oh
the question confuses me lol
i don't think that h is right
oh
i mean o
hmm
sqrt of 4 and 5 is 20 and 25
so that' 55
right?
wait omfg
brain fart
I messed up
lol
mb
good eye sepdron
16 and 25
41
yeah, and subtracted right?
sqrt(9) is 3
ok, now we can solve for sin
you can simplify the sqrt(9)
yeh
yeah, i think so
yeh
I think 2 more questions
then I'm done
finna sleep lol
4:31am
this 1 is confusing my brain
so theres 2 right angle triangles?
1 for tan and 1 for cos
it's the same triangle
i think it's like this one but with tan
yeah
omg I'm so smart
jk lol
k gimme sec to do that
I got it
3/3.16227766
aka 3/sqrt(10)
correct?
yeah, that's right
wait if you read the question it says round to the first decimal
X_X
so I'm wrong then
???
yeah
you only need to calculate cos theta, not theta
,w 3/sqrt(10)
yeah
alr
😄
alr
that's enough for today lol
time to sleep X_X
4:40Am
thanks sepdron
gn
c ya everyday until thursday
cuz I got test lol
hopefully I get to see you man
your the most helpful I've met
peaceee
Before you go
1 more question actually
mb @glacial verge
sorry
so I got this 1 wrong and was wondering why
where do you get those numbers?
oh, i didn't see the little b
haha
sorry I figured out my mistake I think lemme try again
I'm so dumb haha
alright
it should be 27.8, 65.4, 140
am I right?
shouldn't the c also have a decimal point?
hmm
I thought it would be 140 because
it's 140.17
etc
but the rounding chart
not sure how that works but
I just round to the third number
lol
oh, i thought we're rounding to the nearest tenth
but if we round to the nearest integer, yeah that's right
that chart confuses me lol
yeah, idk what it means too
mhm
oh good
idk how the chart works it's weird asf lol
I got 95%
fk
I wanted that 100%
so sad
I missed 1 question
it was cus of rounding I had like 4-5 guys trying to figure out the chart too lol
i think the table is telling that if the degree is rounded to the nearest tenth, the accuracy of the trig functions is accurate to 2 digits after the decimal point
so
cya
@fickle cave Has your question been resolved?
A Shop has 800 parts, out of which 8 are defective. What percent are defective
Probability?
@pliant raft get your own channel
read #❓how-to-get-help
do not post in occupied channels
@royal basin it's not occupied I guess😅
it's occupied until the bot frees it.
Oky
it has another person's name on it
when you post in an unoccupied channel, the bot pins your message and puts your name on the channel
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i need some help understanding logs
specifically, is there a particular order in which the log laws need to be carried out?
kind of like bodmas or smoething
i dont fully understand how they work. for example.
-ln(2) + ln(4)
if you use the addition rule you get
-ln(8) = -2.079
but if u do the subtraction rule first
ln(4) - ln(2)
ln(4/2) = ln(2) = 0.693
so is there a partciluar order u need to do them in, to get the right answer?
are both answers correct?
ℝamonov
i dont get it. all i did what switch the postions of the two values. i didnt factorise the - out or anything.?
in the first method you added the ln(2) and ln(4) first
violating the order of operations
which is what's represented in what I made above
, so what should i have done first?
the second route you took is clear and valid
the first route you took wasn't valid for the reasons mentioned above
im having trouble linking the way logs work with the idea that -a+b != -(a+b)
i get how the idea works with normal numbers, im just having trouble undrstanding that with logs
The rules don't magically stop existing in the presence of logs
-a+b still isn't -(a+b), regardless of how a and b look to you
ln(2) and ln(4) are just numbers
-1 + 1
you would NOT do -(1+1) here, (hopefully)
and that doesn't really change if you have logs or variables or w/e
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can anyone help me w this^
combine the fractions
i was going to use the theorem the limit as theta approaches x, 1-costheta/theta=0
but i wasnt sure how to incorporate it here
i don't think you need that
im honestly lost
can i see your attemt?
sry its prob rlly wrong
$(1-cos(x))^2$ isn't $1-cos^2(x)$
Sepdron
what would i have to do in order to fix it
think of a way to make $a-b$ to $a^2-b^2$
Sepdron
you just squared the a-b
that would be a²-2ab+b²
another way to find it is to factor a²-b²
you multiply it by its complement, (a-b)(a+b)=a²-b²
so multiply 1/1-cosx by 1/1-cosx?
$\frac{1\cdot(1+cos(x))}{(1-cos(x)))\cdot(1+cos(x)}$
Sepdron
wouldnt the denominator equal to 1+cosx^2 which isnt the same as 1+cos^2x
Sepdron
Sepdron
It's the whole expression squared.
$$(a-b)^2 ≠ a^2 - b^2$$
Pencil
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Can someone help me with this
To get the 16 i think its 4y/3
but I dont know how to get the q in there
$\log {\frac{a}{b}}=\log a-\log b$
tomzizek
1st use this
so is it (4y/3) - 1 ?
yes
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Hi
I have a device that uses 87.8kWh on average over a 24 hr period
How do I work out how much this will cost me in power bills?
@vestal edge Has your question been resolved?
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x(t) = 3 sin (t) − sin (3 t)
On paper or in desmos?
I guess you'd need to find (x, y) for some values of t between 0 and 2pi
And then just connect them
do i also need to find the (x,y) that they touch its other?
Real numbers don't touch each other.
what do you mean
That's just the point where y = x, not really significant
Below y(t) and x(t) separately?
is says find the area that is surrounded by the x(t) and y(t)
I think then they'd mean the area of the shape made by (x, y) satisfying those equations
yes
Btw the shape looks like this
I guess you'd need to find x in terms of y and then integrate it from y = 0 to y = 4
(also don't forget to multiply the integral by 4 because of the symmetry)
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The product of two consecutive integers is 8 more than twice times their sum. Find the integers
How do i set this up?
If you an arbitrary integer n, what's an expression for the consecutive number?
i wrote down n+1
What's the product of these two numbers
n^2+n
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Yayyyyyyyy
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hi

I feel like it still feels a little bit off to me
so maybe one of yall can help me with that
this is kinda weird
how it went from a non smooth function, to a smooth function
like
I don't get it man
If you look closely
That smooth function is just a sine wave being vertically shifted upwards by 0.5
in any case
so that basically means
that as long as the function is continuous
its anti derivative will be a smooth function?
smooth means infinitely differentiable iirc
So not.
However, a continuous function should have continuous anti-derivative by FTC if I got it right
interesting
well
well what I meant is like
aight aight
but what i mean is like
for example
if somebody asks for point of inflection, for example at point (1, 1), and asks (is that a point of inflection for h(x) (which is the green function here).
without giving us the graph of h(x)
do we just know that h(x) will be continuous?
and that
point (1, 1) is indeed a point of inflection?
no matter what
@balmy mortar
I'm not sure what you mean.
'Is (1, 1) a point of inflection for h(x)?'
There is no indication h has to be continuous.
but you just said that a continuous function should have a continuous anti-derivative
and that's true even if the function is not differentiable right?
yes.
@distant plinth Has your question been resolved?
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Hello! Is 18:3(3+3) equal to 18:3x(3+3)? If we put it in a calculator the result for the first one will be 1 and for the second its 36. Why is this?
what does : mean? are you sure you wrote it in your calculator correctly
oh, ok! so you have $\frac{18}{3(3+3)}$ and $\frac{18}{3 \times (3+3)}$
yes, those would be equal
ALIAS
it just seems to be an issue with your calculator
can you show me a picture of how you wrote it in the calculator?
Thats a casio thing I think
ooohhh, i know why it's 36
Is it a casio?
its a no name calculator
Because casio does this for user convenience I think, its in the manual
The order of operations is different without the ×
So it is a calculator related problem or the implied multiplication takes the precedence?
Its does implied multiplications first it seems
So you can see it as a problem or as a notation thing
As I said, casio does this for convenience
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i need help with finind area
probably best not to ghost ping helpers, huh?
i forogot the rules and and i needed help but i forgot so then i deleted message
@timid silo Has your question been resolved?
Hint: draw perpendicular lines from O to AB and from O to BC, then draw the line OB. Then consider just that smaller square.
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which values does this series converges to ?
here is my work
value should be 1/7
you wrote 4^n = 4^(n-1) / 4, but it's *4
The first term isn't 4
By correcting the first term and doing what you did again
you got the formula, just use the right starting value
M.E.G. Yottachad
right just multiplying top and bottom by -3
so then you can just use the geometric series equation for this one
b/c |-3/4| < 1
i need n to become n-1 so i can use my sum formula
$\frac{(-3)^{n-1}}{4^n} = \frac 14 \cdot \left(\frac{-3}{4}\right)^{n-1}$
M.E.G. Yottachad
right i just factored out a 4 from the bottom
how did you factor 4 out ?
oh
nvm
thats so smart
thank yo uso much
@flat anvil
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redo your cos^2 integral
oh oops, the last term should be zero
but that doesn't change much, no?
are you sure you did the integral correctly?
how did you go from line 2 to 3?
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For 5 a how am I supposed to find the phase shift to complete the equation
,rotate
@sterile spire Has your question been resolved?
<@&286206848099549185>
The last sentence
@sterile spire Has your question been resolved?
@tardy epoch I’m still confused
@sterile spire Has your question been resolved?
The rung's height is zero when time is zero
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Hello
For this problem it says to find the discontinuities
I know that the denominator can’t be zero or negative
So for the next step can I divide by 2?
???
Imagine f(x) = sin(x)
First it should be >=
Second you should notice that only some values (so not intervals) work
You can’t divide by 2 and cancel the inside
You have $1 - f(2x) \le 0$
n/c
Clearly $f(2x) \neq 2f(x)$ because $f$ is not a linear map
n/c
Think of a simple example. Is sin(pi/2) = 1/2 sin(pi)?
Just. compute them?
Right, so if f(2x) = 2 f(x), then it has to be true for all values of x
You just found a value (x = pi) where they are not equal
Okay, so you have $1 - \sin(2x) \le 0$
n/c
How can you simplify this further?
I can send sin(2x) to the other side
Right, so do that
We're talking about solving the inequality, aren't we?
I’m trying to find the discontinuities
Okay, let's take a step back. Why are we solving that inequality?
Because the square root has to be > 0
That is true, and what else? Specifically, what causes a discontinuity?
0 being in the denominator
Exactly, so right now we're looking at both of those cases.
When is 0 in the denominator?
When the square root makes a 0
Right, so what equation do we need to solve to see when that happens?
The sin?
Be specific, write it out here
Do I need to include the square root in the inequality?
I’m solving for 1-sin(2x)
1-sin(2x)>0
Okay, so you're solving for when it's positive, which also works
So why don't you simplify that inequality
So actually, let me tell you something I did before
Before, we were solving $1 \le \sin(2x)$
n/c
This is because if we solve this inequality, we solve for what we don't want to happen
That is, we don't want the square root to be negative, and we don't want it to be 0
You, on the other hand, are solving for when neither of those things happen
But that won't help us with what we're trying to do, because we're trying to find cases where it goes wrong
Okay, so what happens if sin(2x) = 1?
A zero
Right, and what happens if sin(2x) > 1?
It’s continuous
What do you mean?
There isn’t a discontinuities if sin (2x) is > 1
Wait

Doesn’t sin (2x ) have to be < 1
It does, but I was getting to that
My point was if sin(2x) > 1, then the inside of the square root is negative
Which is the other case that we don't want
Thus $1 \le \sin(2x)$ covers both cases: denominator being 0, and the inside of the square root being negative
n/c
No, you need $1 \le \sin(2x)$
n/c
Didn't we go over that already?
Would you steal my cookies?
Okay, how about we consider 1 = sin(2x)?
Yes.
Isn’t it going to be 1/2 = sin (x)
I really have no clue what the next step is

I really suggest reviewing some khan academy algebra videos
,w plot y = 1 and y = sin(2x) for -20 < x < 20

What's the point of discontinuity for this function?
For sin(2x)?
no, for f(x)
Is sin(2x) = 1 allowed?
Put sin(2x) = 1 in the f(x)
you can't divide by zero, right?
Yea
1 / 0 is bad. 1 / something is bad if something=0 . solve for when something = 0
can you figure out what something is?
$1-\sin(2x)=0$ contributes big time to the discontinuity in f(x)
Ansh
@surreal basin Has your question been resolved?
I know 1 = sin (2x ) will be pi/2
I think
Or pi/4 when I divide everything by 2
Anywa
Thanks guys for helping me
I’ll throw in the towel

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probably $(\log_5(18))^2$
Sneaky
in fact almost certainly that
so i got
(4a^2+4ab+b^2)/c
i also got (4a+2b)/c
and none of them were correct
any help
waittt i know what id id wrong
its
(2a+b-c)^2
idk its not working
can someone help
.close nobodys helping
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i ✨still✨ don’t get why this implies
‘integration is the inverse of differentiation’
if everything is integrated together, then you have everything, "F", if you differentiate everything from another, then you have something observable in F, but unique to other items belonging to F, i.e. "f"
i alright watched its animation
i dont get this at all
what nonsense is this
The first answer uses an intuitive approach, might help you

buxy, did you post this knowing it's a nonsensical non-answer to chromium's question?
I didn't, that is what I use to explain that integrations is the opposite of differentiations
Almost sounds like crank speak lol
@brittle swan if you think of F(x) as the area under the graph of f between a and x, and you nudge x slightly, then the area changes by approximately a rectangle of height f(x)
there is an illustration that can be made to that effect
but i don't have the energy to do that
@brittle swan are you trying to understand intuitively or rigorously why they’re inverses
Do you understand why the statement of FTC 1 means they’re inverses?
this is my question
i can even prove it
so you want to know why int[a,b] f'(x) dx = f(b)-f(a)?
wait
this is ftc2??
This is a corollary of FTC1
what
If you scroll down a little on the Wikipedia article, it says that
(do u know what a corollary is)
(Precisely)
Lol so I assume the “inverse” concept is referring to FTC1
Because FTC2 almost always is talking about the computation $$\int_a^b f(x)dx = F(b) - F(a)$$
abs_0
FTC1 says that $$\frac d{dx} \int_a^x f(t) dt = f(x)$$
abs_0
@brittle swan
yea
So wait what are you asking again lol
why integration reverses differentiation
differentiation is ‘instantaneous rate of change’
integration is ‘area under curve’?????
how the hell are they inverses lol
Ah so you’re asking about intuition
Good luck with that lmao
It’s one of the hardest things to get intuitively imo
Just play around with this idea on your own @brittle swan and it’ll make some sense
integration over an interval (meaning [a,b] where a and b are numbers, or maybe infinities) is area under a curve. Otherwise integration results in a function that is the antiderivative. That's what FTC1 says.
i watched the animation.
But it’s hard to get to a point where you just get it, without having to go “ok I’m adding up the rate of change of the area of the rectangle, which is the same as dadada” every time
@brittle swan did you watch the 3b1b video
yea
ok
Sorry that prob isn’t very helpful lol
this theorem is intuitively true
what isn’t is how it implies integration, differentiation are opposites
You intuitively understand why they’re inverses?
Doesn’t that mean you get why they’re opposites?
i don’t
it should be obvious for you why this theorem implies differentiation reverses integration
not for me
(this is the motivation for ftc2 isn’t it)
You mean the statement of the theorem, right?
i can’t see why it has to do with ‘diff = inverse int’
this statement and ftc1 are complete aliens to one another
to me
We’re working with “functions of functions” (I’ll call it a functional)
composite functions you mean?
inverses act as undo buttons
So if f,g are functionals, then f(g(s(t)) = s(t) for any function s
Wow, how helpful
ie differentiation undoes integration
Start with a function $f(x) = F'(x)$. Then $\frac{d}{dx}(\int_a^xf(t)\ dt) = \frac{d}{dx}(F(x) - F(a)) = F'(x) =f(x)$
it says F’(x) = f(x), where F(x) = int f(t) dt [a, x]
Zybikron
so F is an antiderivative of f
but x is just some upper bound in F’s expression
F is the antiderivative. In words, it’s literally saying “the derivative of the antiderivative is equal to the original function”
so basicallt
‘antiderivative just so happens to be an integral with x acting as an upper bound’
‘and that means integrals are heavily related to derivatives!’
abs_0
?
no
from this
to this
i don’t understand
Do you understand this
yea
Okay
The thing that links
antiderivative is integral with upper bound stuff
to
integrals are inverses of derivatives
is precisely the Fundamental Theorem of Calculus
????
i don’t get this
You don’t get how those could be linked?
(This is rhetorical, you’re not supposed to)
(That’s why it’s called the fundamental theorem of calculus, why it’s so powerful)
(It links these two crazy things that seem totally unrelated)
integral of dy = y + C. do u understand how that's intuitive?
dy/dx = slope. do u understand how that's intuitive?
dy/dx * dx = dy. do u understand how that's intuitive?
integral of dy/dx * dx = y + C. do u understand how that's intuitive?
Bro ok hold up
@dreamy wolf the dy/dx * dx = dy thing always felt so hand wavy and sketchy to me
When dy/dx is presented in calculus, it’s basically a symbol
When did it become concrete values you can multiply by
How? That’s what the proof explains
they’re differentials?
the theorem says ‘if we have f, take the integral of it from a to x, then differentiate it, we get f back’
Exactly
how does it become
this is basically like doing u sub. it's hand wavy yes but it's legal b/c there is rigorous math behind it that lets u do that.
dy = dy * (dx/dx) = dy/dx * dx. this kinda thing u see in physics a lot
How do you get f back?
‘integrals are opposite of derivatives’
This doesn’t sound like opposites to you?
You take a function, integrate it up to x, differentiate with respect to x, and you get the original function back
no
They undo each other
one you differentiate with respect to x
one you integrate with respect to a and x
Broooo I hate that a lot lol
For applications I understand though
if u do A, and then do B, and doing B reverses when u did A isn't that opposites
You can’t go through 10 hoops to avoid small logical problems
It sounds like what you’re really asking is what these bounds are about
Would you still be confused if I said $$F(x) = \int f(t) dt$$ instead?
abs_0
i guess?
isn’t boundless integration introduced after ftc2?
Yes, that’s precisely the issue
we need bounds
And what bounds do we choose? Well a is arbitrary and irrelevant (most people choose it to be 0), but the important part is the x upper bound
everything is with respect to x, there is a t in the integration as a dummy variable because having and the variable x as your bound, and as the variable in your function is.... problematic.
yea i know
@brittle swan Think about it, F takes in a number x and gives you the area under the curve from 0 to x
0?
If you take the derivative of that function, you get f back
(Just think of it as 0 for now, the important part is that it’s irrelevant, you’ll see why in the proof)
yea i know why it’s irrelevant
Ok
I sorta think I get why you don’t get it
When we say “derivative of f” what are we saying?
It’s a new function f’ such that f’(x) is the slope of the tangent line to the graph of f at x
When we say “integral of f” what are we saying? It’s a new function $F(x)$ such that $$F(x) = \int_a^x f(t)dt$$
abs_0
@brittle swan FTC1 establishes that f’ and F are opposites, according to these above definitions
the hell
Translating to colloquial language, you can say “derivatives and integrals are opposites”
Did that make any sense at all lol
not really
Dksichdiejf
(i’ve been asking this for 3 days)
Really
(yes)
:(
@raven spire use another channel
It's relevant to the topic!
Oh
@brittle swan I think part of it is that your question requires us to understand something you don’t get in your head
I will say that I don’t really get exactly what you don’t get, like sorta but not really lol
or rather, what's already been tried
The integral of a function is the area under the curve! ✓ I can see that visually.. and it's fine!
But ..
The derivative of the integral,i.e., the derivative of the area under the curve.... returns the function ;-; how do you visualize that?
Ok @brittle swan for this person can you just try to phrase your question in the most exact words you can
bottom text
It’s very difficult
and that maybe answers my question
I spent a while trying to force my brain to accept it, and it’s just plainly an unintuitive concept
:p
Unintuitive**
is it really that unintuitive?
The tangent slope doing the opposite of the area under the function? I mean
Call me crazy but those sound like totally different things lol
it seems to me that between $\int_a^x$ and $\int_a^{x+h}$ where $h$ is small, all you're doing is adding an infinitesimal rectangle of height $f(x)$ and width $h$
Camilleone
what i think about is a rectangle. length f(x). side length dx. integral u get the area so it's f(x)dx. derivative u divide by dx u get back f(x). and then i think about riemann sum
and that is exactly the rate of change of the area
But whenever you think about how they’re opposites, you must go through this thought process every time
At least, for me
Intuitive means I don’t have to go through any thought process at all, I just get it in my gut
Oooooooooo omg that's smart >_<
like one way to view, is change of area
and dumb of me at the samee time
T_T

the what?
this explains d/dx (int), not int (d/dx)
i must have missed that
How does the "derivative is the slope of tangent to a function at some point" comes into equation here 
Does it have to do with, slope of tangent being a rate of change of function 👀
Yes I believe
oh i see
Yes, the slope of the tangent is “instantaneous rate of change”
(Really, rate of change as h, the distance between the points, approaches 0)
Got that... now the int(d/dx) part plz... as chromium asked
the first problem with any argument of int (d/dx) is the introduction of a constant which leads to many antiderivatives
Changing areas makes sense… area under changes doesn’t
like, many functions all differing by constants have the same tangent function
i believe this is what's making the arguments hard to understand intuitively
so to understand this we have to go back to $\int_a^x$
Camilleone
the derivative, as you know, is the rate of change function
so let's say you start with a function f, and then you differentiated it to find the derivative f'
the integral of f' can be understood as infinitesimal addition of all the little rates of changes at each point
huh..?
which means that now to get $\int_a^x f'(x) dx$, what you want is the total sum of all the little changes of $f$ from $a$ to $x$, which ends up as the difference between $f(x)$ and $f(a)$, i.e. $f(x) - f(a)$
Camilleone
i can’t visualise this
Ohhh cause a rectangle with 0 with is the same as the height basically right
yeah
Wait no that doesn’t make sense
well
i admit it isn't that well-worded
what i should have said was
take for example a rate of change at a point $x$
Camilleone
for h small, between x and x+h you basically add an infinitesimal "increase" of the function by that rate of change - of course if the rate of change is negative your function decreases, but that's not important