#help-36
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I want to verify if it’s correct with you
This thing
And what about the x^2+y^2=0 part?
$\forall z\in \mathbb{Q} : : : xyz \leq 0$
tales
whats of the negation of being equal
Ohhh not equal
Like /=
So negating statements is just changing “there exist” to “for all” and then just change whatever condition they have to the opposite?
We keep the “being an element of what set” constant? That’s the only thing we don’t change?
yes
Does the imply symbol need to change or is this good?
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what would then be the Standard deviation of lead time ??? (considering months as time unit for calculations)
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how do I solve |x^2 - 8x +6| < 6
compute the roots first of all
wdym
find the roots.
consider two cases
x^2 - 8x + 6 < 6
or
x^2 - 8x + 6 < -6
what like ( x - 8 )( x + 0 ) < 0
and ( x - 6 )( x - 2 ) <0
alright
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Hello, can someone help me confirm my proof is correct?
what proof?
the proof states: ax+b is even if x is odd or b is even
how about a?
doesnt say
then I don't think it fully correct
I just flipped the argument around and said: if x is even and b is odd then ax+b is odd
and then I set x = 2k and b = 2k+1
$3*1+4$
Jon
if you try that it will equals to 7
damn
which x is odd and b is even
by the way, this is a way to disprove something, just try to use some random numbers or special numbers to see if it works
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Hello! I need help with a combination problem
There are 8 points drawn on a piece of paper such that no three of the points are collinear
a. How many distinct lines joining these points can be drawn
b. How many distinct triangles whose vertices are among the 8 points can be drawn
if you draw a line on any of the given 8 points
how many points do you use
2?
Do I multiply or divide?? 4 or 16??
have you learned choose
4?
does the first question ask for the maximum lines that can be drawn?
hop into #discussion
Honestly idk but the question is just written like that I didn't change anything
The question says no three of the points are collinear I'm not sure what that means tho
What does that mean
two points may lie on the same line
which they always do
but no three points can lie on the same line
I misinterpreted it
the question is completely right
So what do I do?
consider one point out of the 8
Then?
how may lines can you draw to the remaining points
I'm sorry I'm stil confused TT
like mark 8 points on any piece of paper
consider one point
and count how many lines can you draw so that the lines passes through that point and any other point
wdym by consider one point?? I'm rlly slow sorryyyy TT
Okay let's go by a different method
if you draw a line on any of the given 8 points how many points do you use
2
and how many points are available?
8
can you conclude that each pair of points determines a distinct line
like if you chose any two points at random, they form a distinct line
Is it 4?? There's 4 pairs in 8
no
there are 4 distinct pairs in 8 and we're not looking for distinct pairs
what we're doing here is basically choosing two points out of eight
can you write that in combination notation?
N=8 r= 2 right??
yes
It's 28
yes
Is that it for part a??
yes
Can you also explain part b??
now how many points you need to form a triangle?
3
can you again conclude that any 3 points would form a distinct triangle?
I do the combination notation again??
56
yes
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i dont rly know where to start
do you remember any trig formulas that might be relevant here?
hint: double angle
what trig identity did you use?
sin2(theta)=2sin(theta)*cos(theta)
i havent done much trig before so i dont come up with them on the spot, the hint was usefull!
yes that's it, , sin(2theta)
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Hi! Could someone help with this?
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Hi, how would i do this?
Sorry you guys have to read this essay lol
4 facilities: 2x
[2,4] facilities: 3x
0 facilities: 4x
i think
Let the people who use 4 facilities be F4, who uses 3 be F3, who uses 2 be F2, who uses 1 be F1. People who don't use any be F0
So
F0 = 2xF4
F0+F1+F2+F3+F4=1160
There is also the line that says for every person who use F facilities, there are exactly 3 persons who use AT LEAST F-1 facilities
Which I don't know how to take advantage of mathematically
right
Let's say that for every person of F4 people there are exactly 3 people who use at least 3 facilities
Meaning they may use 3 or 4
yeah i think that's what i wrote out
for every other person you have three so if we use n as a counting index
2n is the 4 facilities
and 3n is the [2,4] facilities
cuz for every 2 in 4 faciities you have 3 in the [2,4] faciities, no?
maybe i should ping helpers too? idk
could someone help
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<@&286206848099549185> could someone help?
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<@&286206848099549185> 😭 could someone help please
no
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@tawny ivy Has your question been resolved?
Nope <@&286206848099549185>
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With the formulas KA = 0.24x + 55 and KG = 0.32x + 49 you can calculate how much you have to pay at the car sharing companies AutoShare and GreenCars if you rent a car for one day and drive x kilometers. Here the costs are K in euros.
a Investigate by solving an inequality how many kilometers of driving GreenCars is cheaper than AutoShare.
b For how many kilometers is AutoShare at least 10 euros cheaper than GreenCars?
(0.24x+55<0.32x+49-10
0.24x-0.32x<49-10-55
-0.08x<-16
x>200
AutoShare is at least 10 euros cheaper than GreenCar when driving more than 200 km.)-> answer from school
Why do they do -10 at greencars formula when autoshare is supposed to be 10 cheaper
Please ping me when someone replies!
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Let $\Delta:X \rightarrow X\times X$ be diagonal map where $X$ is manifold. It's derivative at point $p$ is $d \Delta_p(v) = (v,v) $ for $v \in T_pX$.
My question is, why is pullback $d \Delta^_p (\eta,\zeta) $ equal to $\eta +\zeta$ where $\eta ,\zeta \in T^_p X$?
Gigrise
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is the answer 4.5 im just asking because its really annoying to get questions wrong on ixl
well howd u do the problem
ok so first i figured out that i needed to use tan so i just did tan(27)=square root of 5/TU
and then i multiplied by tu
on both sides
then i just put tan(27) into the calculator
gave me 0.509
howd you figure out that u needed to use tan
tbh idk how to explain i kinda just used instincts because tu is adjacent to angle t and square root of 5 is opposite to angle t
ok so heres the thing
theres an angle, theres a side opposite the angle, a side adjacent to the angle, and the hypotenuse
TU is the hypotenuse
the hypotenuse is the side opposite the right angle
always.
correct
so then id have to do sin
yea
alr hold up imma redo my work and then give an update of what i get
ping when done
@fathom walrus alr so i got 4.9555556, ixl is asking me to round it to nearest tenth so would it be 5?
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im confused how to graph this bedcause i always end up with the asypmtote being above the graph
@silent heron Has your question been resolved?
shouldnt your hor asymptote be y = -5
yeah which is why im confused that my y was -8
how did you even get that
i just transalated the previpous one down 5 and right 3 and then multiplied the y values by 2
the original asymptote for 4^x-3 is y=0
shift it down 5 units
so your new asymptote is y = -5
i need to find the points for x=0 and x=1 to make a graph and i thinkthats where i messed up
i plugged them into to get 1 and 4 and just used ther tranformations to get -4 and -1
then i multiplied those by 2
to get -8 and -2
but i messed up because it cant be below -5
eh idk i think its easier if you work with the original equation itself
seems like x = 3 and x = 4 will give you a whole number
,rccw
yeah seems about right
alr ty
then you just draw it flatter as x goes to the left
just like the normal exponential graphs
o yeah
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Need help on the other 3 questions on conditional probability
same is the probability and republican is the given right?
for the first one, yes
you're computing the probability that someone believes the economy is the same given that you know they're republican
yeah I simply did the sum of republicans divided by the total of those people
but besides that for the P(same | Republican) I have to divide same and republican by something right?
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@woven harness Has your question been resolved?
For P(same|Republican) you are only considering the adults who chose "Republican", so the denominator is the sum of Republican
The numerator is the adults who chose "same" among those who chose "Republican" so it's 104
Besides did you calculate the second question correctly? Seems it didn't match mine
ah ok
yeah went to fast on a too easy question with that
and I'm guessing the Republican | same is 186/104
Noooo the probability cannot exceed 1
yeah just caculated earlier
its a whole number
so what should I do in its place?
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what's a mean of variable change?... How do I solve part (a) and use it to solve (b)... Additionally, in the reduction formula question. I don't understand what he means by "Establish" like should i prove the formula given or what?
That is a typo, it should say "means" and yes you should prove the reduction formula.
@violet bramble Has your question been resolved?
okay byt i still don't understand how to answer part a
but*
in point a) you have to derive the given formula using appropriate substitution, because the change of the integration variable can be obtained by substitution
so sorry but can you like show me a working cuz i don't understand
Have you ever integrated using substitution?
yea i did but never came across a question like this
I just don't understand how we should do it
take the integral on the right-hand side, and use the substitution u = a + b - x
and try to obtain the integral in the simplest form possible
yw)
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\textbf{\textit{\textcolor{blue}{Question:}}}
An absentminded worker does not remember which of his 12 keys will open his office
door. If he tries them at random and with replacement:
\begin{enumerate}
\item On average, how many keys should he try before his door opens?
\item What is the probability that he opens his office door after only three tries?
\end{enumerate}
\textbf{\textit{\textcolor{red}{My answer:}}}
\begin{enumerate}
\item The worker is trying the keys with replacement, which means after each try, he puts the key back, and each key has an equal chance of being picked again. This is a geometric distribution problem. The expected value (average) of a geometric distribution is 1/p, where p is the probability of success on each trial. In this case, the probability of success (picking the right key) is 1/12 (since there are 12 keys and only 1 will open the door). So, on average, he should expect to try keys $1/(1/12) = 12$ times before the door opens.
\item The probability that he opens the door on the third try (which means the first two tries were unsuccessful, and the third try is successful) can be calculated using the formula for the probability mass function of a geometric distribution: $p*(1-p)^{n-1}$ where p is the probability of success on each trial, and n is the number of trials. Here, p = 1/12 and n = 3. So, the probability is $(1/12)(1 - 1/12)^{3-1} = (1/12)(11/12)^2 \approx 0.071$ or about 7.1%.
\end{enumerate}
Trenton
Can anyone help me to have a check of my answers? Thanks!
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Find I_0, I_1 etc
x and ln(sinx)
But
how do i use u then
theres no cotx in that
x ln(sinx) , -x - cotx ,
oh iseeee
they cancel
nah man
tf
I10
i do 10 integrations
tf
There should be some general pattern you can find
Maybe I_n = 1_(n-1) some recursive formula
oo
yeee
I(n+2) = abc - I(n)
abc is uhhh
cot^(n+1)x/n+1
@silver maple what now

I don't know

ah ok
i think i found it
Yee got it
Just had to put n in that 0 123 add allofthen
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Can someone verify this ?
looks fine
.
\begin{align*}
x^3+x-1&=0\
x^3+x&=1\
x(x^2+1)&=1\
x&=\frac{1}{x^2+1}
\end{align*}
Desync
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Solve the compound inequality and give your answer in interval notation.
4x-4>0 AND -1x-5>=-7
@split oak Has your question been resolved?
!status
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
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Does the number $\binom{k}{k_1,k_2,\dots,k_n} / n!$ have a special name?
bigpufik
if no, were does it appear?
@modern wraith Has your question been resolved?
So I’m doing a physics problem right
Accl=(m1*g)/M1+M2
M1 is the weight in 10 gram increments
What it’s pulling is 500g
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So like the formula I have is the weight*gravity/ the sum of the two
Ignoring friction
But like
The data vs theoretical is so off it’s crazy
Any suggestion on what I missed???
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$\sin^4\left(\frac{\pi}{8}\right)+\sin^4\left(\frac{3\pi}{8}\right)+\sin^4\left(\frac{5\pi}{8}\right)+\sin^4\left(\frac{7\pi}{\left(8\right)}\right)$
Why am. I here
I first re-wrote the last two terms to obtain
$2\sin^4\left(\frac{\pi}{8}\right)+2\sin^4\left(\frac{3\pi}{8}\right)$
Why am. I here
now to solve this do I need to find sin(pi/8) or is there a way around that
oh
I just use the half angle formlae, right?
$\left(\frac{\left(1-\cos\left(\frac{\pi}{4}\right)\right)^2}{4}\right)$
Why am. I here
oh
so that's just cos^4(pi/8)
I complete the square then, I pressume?
hmm, $1=sin^4(pi/8)+cos^4(pi/8)+2sin^2(pi/8)cos^2(pi/8)$
Why am. I here
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$m^2\cos\left(\frac{2\pi}{15}\right)\cos\left(\frac{4\pi}{15}\right)\cos\left(\frac{8\pi}{15}\right)\cos\left(\frac{14\pi}{15}\right)=n^2$
Why am. I here
I started by re-wirting this as
$-m^2\cos\left(\frac{2\pi}{15}\right)\cos\left(\frac{4\pi}{15}\right)\cos\left(\frac{7\pi}{15}\right)\cos\left(\frac{14\pi}{15}\right)=n^2$
now I use the double angle identities, I guess?
though won't that be rather nasty
i dont see what did you re write
cos(8pi/15)=-cos(7pi/5)
Why am. I here
okay
yeah, that doesn't seem to help too much
this
just two constnats, I think
what was your method? product to sum?
I think
I have found a way to solve this
But the only problem lies in finding the value of cos14pi/15
,w cos(14pi/15)
no, that would be -cos(13π/15)
What do you mean
I feel like it would be a lot easier with 16pi/15
You can generate that!
yeah please
What I did was multiply 2sin2pi/15
Yes, yes.
You get m^2/n^2 ratio use dividendo
oh, ok
ykw, this seems really interesting, I want to think about this a bit more, can I close this for now? Sorry
Sure.
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(Dividendo)*
My bad
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can someone pls help me with this
Did you expand it
i tried, im not able to solve it. when i put it in the calculator, it either says timed out or gives me different values each time
Show your work
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One way to find the sum of all natural numbers up to n, S_n, is to say something like:
S_n = 1+2+3+...+n
So:
S_n = An^2+Bn+C -- why??
Conditions:
* S_(n+1) = S_n + (n+1)
* S_1 = 1
Now, find A, B & C such that the conditions are true.
An^2+Bn+C+(n+1) = A(n+1)^2+B(n+1)+C
<-> An^2+Bn+C+n+1=An^2+2An+A+Bn+B+C
<-> An^2 + (B+1)n + (C+1) = An^2 + (2A+B)n + A+B+C
So we get the following equations:
* A=A
* B+1=2A+B
* A+B+C=C+1
We now solve these.
B+1=2A+B <-> 2A=1 <-> A=1/2
A+B+C=C+1 <-> A+B=1 <-> B=1/2
Since A=1/2 and B=1/2, C=0.
So:
S_n=1/2n^2+1/2n
=1/2(n^2+n)
I understand the idea of assuming that something can be written as something else and then calculating the constants, but I don't understand why you assume that e.g. this sum can be written as An^2+Bn+C or why the sum 1+2^2+3^2+4^2+...+n^2 can be written as An^3+Bn^2+Cn+D? Please help ♥️
(oops I didn't give any argument to make sure that S_1=1 but I suppose you'd just test the equation? Or is there a better way? I would like someone to tell me what the absolute best way to approach these things is)
You don't assume them to be anything, they just turned out to be regular polynomials
Take fibonacci series to account
You do assume that S_n is a quadratic
yes you do
You don't have to
Wdym?
With this method you do have to
you do for this method to work
I'm asking about this method specifically to be clear
You can prove the sum of n numbers without assuming S_n to be anything
But then you're not using this method are you?
dawg i think you're misunderstanding the question
My goal isn't to prove what the sum of those n numbers is. That's easy. My goal is to learn the reasoning behind doing it with this particular method (which is "overkill" here)
Is he asking why 1 + 2 ... is quadratic and 1^2 + 2^2 ... is cubic?
Yeah I'm asking why you can assume that 1+2+... is quadratic and why e.g. 1^2+2^2+... is cubic
pretty much
I can only give you like a motivation why you would assume it.
Say f(n) is the sum of first n numbers to the m'th power.
Then f(n + 1) - f(n) = (n + 1)^m
And that looks like a function of degree m + 1
Yeah, that's actually enough evidence if you assume it has to be a polynomial
That's basically the condition I wrote as well, but generalized to mth power
And not only does it look like one, if it's a polynomial it has to have degree m+1
Because the biggest degree term will cancel
Yes. I mean it isnt a proof that f is polynomial of degree m + 1. But it is enough motivation that you can assume it is and find out if it is yourself
Like you can have assume it is then prove your result via induction
there's a simpler answer
For assuming that 1^2+2^2+3^2+... is quadratic my book says "Since there are n terms and the biggest one is of size n^2, it is reasonable to think that S_n can be written An^3+Bn^2+Cn+D ..."
I don't understand the full reasoning there though
Yeah that's not enough information
the growth of the S if S satisfies S_(n+1) = S_n + (n+1) is linear, so S is quadratic by basic calculus
similar with higher orders
I mean for a polynomial to change for a square it really has to be 3rd degree polynomial
Everything above is too much and everything under is too little
If it is a polynomial then it has to be 3rd degree i think
Isn't that what casework said too
yeah that's fair. This is before calculus (I haven't started with it) but I understand
Actually it must be m+1, and can't be anything higher or lower, If you take (m+1)th derivative:
f^(m+1)(n+1) = f^(m+1)(n)
so f^(m+1)(n) = C
so degree of f must be m+1
And by just observing, it can't be lower than m+1
Not sure if there's another way to show this
Btw what is it called when you have some equation which you just assume to be of some form, perhaps with an educated guess, and then calculate the values for the constants to satisfy the conditions? There's a word for it in my language but I don't know if there is in english
(google translate wasn't helping)
What language do you speak, and what's the word
So basically like bashing
But that isnt a translation
It just means to brute force
So there's no commonly used word in math for this?
Not that I'm aware of
So you're supposed to just write "Let ... = ..." or "Assume that ... = ..." in all these cases?
You mean as like a math symbol?
No it's just a nice word
I think it is
I bet it is commonly used
Yeah "Ansatz is german but is also used in english"
damn
Well now I know 😄 not sure if I'm supposed to use it in mathematical text though
ur chatgpt response seems to suggest it's ok but i don't trust chatgpt
Google backs it up too
TIL 😄
Or just use the word "motivation"
"by using the motivation we got from <insert step>"
It's not really the same thing
An ansats in swedish is basically when you make some assumption, work it out and then confirm it latern on when it actually gives you solutions
So basically ramanujan = ansats
in this page they use the word ansatz similarly to how it's used in swedish
You can change the word a little to make it a bit more ergonomic in swedish but yeah it's basically the same
👀
😂
Ironically, obscure is an obscure word.
true
Anyways I think we got way off topic
I'm still a bit sad I didn't understand the full reasoning behind what the book says because I feel like there has to be something you can add to it for it to make perfect sense
I guess I'll just let it go
The base case is I think easy to understand
1 + 2 + ...
Well now that I said it, it is not easy
It is only obvious that it can't be linear
Yeah
Well I think the base case is easy now
You basically have a bunch of numbers in a pattern and the difference between those numbers is just growing by some constant
You can view this as having acceleraiton=1. Then velocity (difference) is linear, and then position is quadratic
Like a geometrical meaning?
The book says: Since there are n terms and the biggest one is of size n^2, it is reasonable to believe that S_n can be written as An^3+Bn^2+Cn+D
I just don't understand why "it's reasonably to believe that S_n can be written as ..." from that
(Probably)Because it has to be higher than 2
So just An^4+... feels to high and An^2+... is too low?
i havent had sleep ok
We are going down hill in channel list
we sure are
I think we just have to let it go, we proved it too
You're welcome!
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(tan-3)(tan+2)
what are the 4 solutions?
huh
(tan-3)(tan+2) isn't an equation
=0
you're not gonna get help if nobody understands what you're asking
(tan-3)(tan+2)=0
You can't just write tan-3 and tan+2, do u mean tan(-3) and tan(2)?
nvm, I guess u mean tan(x)-3 and tan(x)+2?
yes the second
so x = 3 and -2
no
tan(x)=3 and -2
there are two values for tan(x)
which satisfy the equation
Then you need the arctan(x)
Are we working with degrees or radians?
degrees
ok
So two of the solutions are arctan(-2) and arctan(3). arctan(x) doesn't give you all the possible values of x though
Yeah I learned the graphs for the rest
You were taught to use graphs to find the rest of the solutions?
yes
so i memorised the sin cos tan graphs
😮
Just so u know: y=tanx->x=arctan(y). The other values of x are x+n*pi for some integer n.
You can understand this with graphs. It takes pi radians for the tan function to complete one segment
And so at x+n*pi radians it will repeat itself
This means that there are infinitely many solutions to an equation like y=tanx
In your problem, you have tanx=3 and tanx=-2, and ur working with degrees. So instead of pi, we'll use 180.
tanx=3->x=arctan(3)+180n for some integer n
tanx=-2->x=arctan(-2)+180n for some integer n
* arctan(3)=71.5650512 degrees.
* arctan(-2)=-63.4349488 degrees.
* arctan(3)+180=251.5650512
* arctan(3)-180=-108.4349488
* arctan(3)-2*180=-288.4349488
* arctan(-2)+180=116.5650512
* arctan(-2)+2*180=296.5650512
* arctan(-2)-180=-243.4349488
and so on
There are infinitely many solutions.
The ones in the message above are all the solutions assuming x is in the interval -360<=x<=360 (degrees)
If there really are only four solutions, then the question is either wrong or there's something left out
Do you understand? y=arctan(x) gives one value for what y can be since arctan is a function. Thing is tan(y) is the same if we rotate y by 180 degrees, or 2*180 degrees, and so on
not entirely the same
e.g. y=sin(x+n*pi) for some integer n will oscillate between being negative and positive, but the absolute value remains the same
Same for cos
Here is a picture of y=sinx and then I drew lines at x=pi, x=2pi and x=3pi
The sine wave is symmetrical in the sense that the bottom parts and the top parts have the same shape
This means that if you add pi to your value of x, the value of y will be negative that which it was before
For example, look at this:
At x=2+pi, y is negative.
At x=2+2pi, y is the same as it was before but instead positive. We just flipped the sine wave upside down basically
at x=2+3pi, y again became negative, and so on. But the absolute value of y remains the same
So, this is all because the sine wave repeats itself every pi units (and since the negative parts of the sine wave at x=a have the same absolute value as the positive parts of the sine wave at x=a+pi for some number a)
I get it
and hopefully cos follows the same rules sin does?
Oh actually cos just connected in my head
thank you a lot
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some one just solve this
do you know what the symbols mean?
ye
its the intersection of x and y so c and f
good
now visualize that region
you now need to do that cup Z
what does that do
its a union so the answer would be a
bingo!
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Question:
"The population in a city follows this mathematical model (Mathematical model linked as an image with this post)
where t is the amount of years after the year 2010. After how many years will the population of the city have increased by 20%?"
I simply do not understand what process I'm meant to take in order to solve this question, I'm lost and unsure how to start.
Any help is appreciated. Thank you for taking your time to help! 🫰
try to rewrite N as 20% larger than N0, then solve for t with logarithms
So I did 1.2N = 10^0.006t
=
lg (1,2N) / 0,006 = 0,006t / 0,006
=
t = lg (1.2N) / 0,006
= approx 13.2N
Though, I got the years correct (13.2), I'm still left with an N variable, am I allowed to just toss that and give an answer of 13.2 or what?
nvm i'm stupid
:D
1.2 = 10^0.006t is enuff no?
right that fixes it haha
Thank you for the help! :D @zenith pollen I'll be clearing this channel for now, so other can use it!
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can someone give me a rough idea of how to solve these, I feel like I got the general idea but I just need a good explanation
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hello?
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hello everyone, having an issue with this integral. i can get to the point where it requires trig substitution but things gets a little messy for me after that. currently at:
What's the original?
^
@fleet grove Has your question been resolved?
?
oof this is slightly unfortunate
if i got here i'd probably just finish it with trig sub
it's fairly doable although not very fun
@fleet grove Has your question been resolved?
yeah its not
i think i got it right but the professor answer is different
sooo
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This is a goes of elevation and depression
Can someone please help me with these
This is the format my teacher uses
That's for angles of elevation tho i don't have a angle of depression format
Can someone help me
<@&286206848099549185>
@errant mist Has your question been resolved?
someone please help me
theres only 4
question 1 and 4
lets do 1
ok
lemme see
first i would need to draw the angle but i dont know it it should look
right here
From a point A, 100m above sea level, a sailor sights a boat at an angle of depression as 27 degrees. Calculate the horizontal distance fo the boat from the sailor.
yea
damnit i keep forgetting i dont have a god damn drawing pad
do you know what an angle of depression is
kinda
i mean using this image can you make a picture of the sailor
in the problem
can you draw a triangle with the given angle
not really
well okay the sailor is up on a pole right
the triangle shouldnt be the specific angle
yes
and he sees a boat
its presumably on the surface of the water
Can you see how this makes a triangle?
You should be able to label at least...one side and one angle if so
wait let me draw how i think it should look and show you
okay, sure
youre almost there, except the sailor is up at the top
otherwise, i think everything in this picture is right
its more like this
Ohh
Ohhhh
Wait
So he's looking down?
yea
hes in a tower or whatever, 100 meters above sea level
and hes looking down at the surface of the water, where he sees a boat
A light house?
Ok I understand that part
these things
Let me right it
Oh
Oh I see
So I finish drawing the triangle
Now for the question
@mint orbit
yea so youre on the way here
i just added an extra angle marker here from your images
can you see how the red angle is complement to the 27 degrees?
i mean, together they must be 90 degrees
we wanna use this to solve for the red angle (red in my image)
sorry im back something ergent happened
Should the 27 degree be in the curve thing
curve thing?
That's what my teacher says
To close the black and green line
Oh I see
Wait
I'm suppose to be trying to find the missing part
the problem is we have one side and one angle
Which in this case I think it's the bottom line that's adjacent
its not enough to solve for what we need
So in this case we have the opposite and hypotonuse
And I'm trying to get the adjacent which is the bottom line
im running out of colors
yea want the bottom line, yea
i drew a red arrow
but we have one side length
100m
and one angle
90 degrees
do you see how 27 degrees is outside the triangle?
Um not really cuz my teacher didn't tell us about that
this is just definitions
you see the side with the red arrow, thats what we want to know, yea?
Yes
and the information were given is the height, 100 m
thats part of the triangle
and were given the 27 degrees angle of depression
Yes
that is not part of the triangle
Oh...
its outside the triangle, you see?
it connects a side of the triangle and just that green line
Wsit
that green line isnt part of the triangle
Right here the angle of depression shows that it goes inside
Is that what I should do?
you need another angle inside the triangle
So I just put the 27 degrees at the bottom inside
if you understand why thats true, sure=
you can find it now
Because we are calculating the distance of the sailor from the boat horizontally
yea, you definitely want the bottom
and you want the adjacent
SOH CAH TOA
I write
Given: opp/angle
Need: adj?
That's what my teacher do
Yes
so not sine
dont over think it
you have the opposite, like you said
The opposite we have measurements and the adjacent we need measurements
jan Niku
jan Niku
heres an explicit formula for the side you want
why we dont use the hypotonuese?
we dont have or want it
oh
we dont know what it is, and we havent been asked to find it
so that means we shouldnt use any formula that involves it
ohhh
oh i understand
so we are given: opp/angle
we need: adj
and then Tan =opp/adj
since thats what we using
this requires that you can identify that you know the side opposite the angle
and you don't care about the hypotenuse
yes so we ignore that'
so is this correct so far
you may wanna get in the habit of writing stuff out and circling or coloring or otherwise marking stuff
like, you could write out this
ok wait
yea
from SOH CAH TOA
im writing it
and i looked at the diagram and i saw
we know theta (its the angle)
and we know opp
so i drew a green line next to each
and we dont know adj, but we want to
so i drew a red line
if you write an equation with all green lines except one red line
you can solve it for the answer
im not following
its not important its just to help you but if you dont follow it it doesnt matter
theres nothing left to do but identify you are done
you need a calculator now
you can solve for the answer
you can use whatever tool is helpful to you
no i mean dont we need to cross multiply before we get to our answer
ok so
after writing TanQ= opp/adj
wait
@mint orbit put a random letter at the bottom line
right?
what? why?
my teacher did it
all you need to do is isolate adjacent
ok
so after this
right, just isolate the thing you want
do i write Tan27*=I/100 x 100?
the 100 is the 100m
cuz thats what my teacher told us
to do for angle of elevation
and they are kinda simiplar
no
i cannot really say anything else @errant mist
i gave you the answer
you just type it into the calculator
ok thxs
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I have a question about restrictions
fire away
Ok so let's say I had a denominator of:
Where x + 4 is under the square root
When finding the restrictions, would I say whatever is under the square root can not be greater than or equal to 0, and then for the entire expression, would I say it can not equal 0?
Yep
Thank you
actually you would say that whatever is under the square root cannot be less than 0
but yeah
Would it just be less than, or less than and equal to?
less than. it's fine for it to be equal to 0 because the square root of 0 is just 0
you would write that $x + 4 \geq 0$
Awesam
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The smallest possible integer having the remainders 2,3 and 6 when divided by 3,5 and 11 respectively lies between what?
41 and 50, 61 and 70, 71 and 80 81 and 90 or 91 and 100
I know it’s 81 and 90, I just don’t know how to solve it without blind guessing
Are you aware of the Chinese remainder theorem?