[Boards: 3 / a / aco / adv / an / asp / b / bant / biz / c / can / cgl / ck / cm / co / cock / d / diy / e / fa / fap / fit / fitlit / g / gd / gif / h / hc / his / hm / hr / i / ic / int / jp / k / lgbt / lit / m / mlp / mlpol / mo / mtv / mu / n / news / o / out / outsoc / p / po / pol / qa / qst / r / r9k / s / s4s / sci / soc / sp / spa / t / tg / toy / trash / trv / tv / u / v / vg / vint / vip / vp / vr / w / wg / wsg / wsr / x / y ] [Search | Free Show | Home]

A few months back I asked this problem. A few answers were posted;

This is a blue board which means that it's for everybody (Safe For Work content only). If you see any adult content, please report it.

Thread replies: 26
Thread images: 7

File: circles.png (11KB, 504x492px) Image search: [Google]
circles.png
11KB, 504x492px
A few months back I asked this problem. A few answers were posted; all of them were different and probably none of them were right. Is /sci/ ready for round two?
>>
>>8865690
>Can you do my homework?
No.
>>
>>8865742
I don't think you grasp the nature of this problem
>>
>>8865690
b
b for bye
>>
>>8865770
I thought everyone was a brainlet when couldn't solve it. But kids these days don't even try. I bet you're a liberal, huh?
>>
I've taken through calc ii and I don't have a clue how to solve this.
>>
>>8865784
Depends what you mean by liberal
>>
File: solution.png (8KB, 770x114px) Image search: [Google]
solution.png
8KB, 770x114px
>>8865791
one brave anon tried and got this horrible mess
(One of the probably-not-right answers)
>>
File: 6242345862.jpg (14KB, 249x300px) Image search: [Google]
6242345862.jpg
14KB, 249x300px
>a and b are constants where a < b
>>
>>8865791
Well, as b approaches infinity, x approaches b. That's all I've got.
>>
>>8865690
Here's the expression for the area of the intersection of the two circles

[eqn]
\begin{cases}
1 & (a>0\land x=-a-b)\lor (a>0\land x=a+b) \\
\frac{1}{2} \left(2 a^2 \tan ^{-1}\left(\frac{a^2-b^2+x^2}{2 x \sqrt{a^2-\frac{\left(a^2-b^2+x^2\right)^2}{4 x^2}}}\right)+\pi a^2+2 b^2 \tan ^{-1}\left(\frac{a^2-b^2-x^2}{\sqrt{-a^4+2 a^2 \left(b^2+x^2\right)-\left(b^2-x^2\right)^2}}\right)-\sqrt{-a^4+2 a^2 b^2+2 a^2 x^2-b^4+2 b^2 x^2-x^4}+\pi b^2\right) & a>0\land -a-b<x<a-b \\
\frac{1}{2} \left(\pi a^2-2 a^2 \tan ^{-1}\left(\frac{a^2-b^2+x^2}{\sqrt{-a^4+2 a^2 \left(b^2+x^2\right)-\left(b^2-x^2\right)^2}}\right)-2 b^2 \tan ^{-1}\left(\frac{-a^2+b^2+x^2}{\sqrt{-a^4+2 a^2 \left(b^2+x^2\right)-\left(b^2-x^2\right)^2}}\right)-\sqrt{-a^4+2 a^2 b^2+2 a^2 x^2-b^4+2 b^2 x^2-x^4}+\pi b^2\right) & a>0\land b-a<x<a+b \\
\pi (b+x)^2 & a>0\land x=a-b \\
\pi a^2 & a>0\land a-b<x<b-a
\end{cases}
[/eqn]

just set it equal to pi a^2 / 2 and solve for x
>>
File: 1485158637042s.jpg (2KB, 104x124px) Image search: [Google]
1485158637042s.jpg
2KB, 104x124px
>>8865841
>solve for x
fuck that
>>
>>8865841
good man
>>
File: 1490981654069.jpg (10KB, 186x356px) Image search: [Google]
1490981654069.jpg
10KB, 186x356px
>>8865841
>>
File: hänmänsynttävää.png (158KB, 666x607px) Image search: [Google]
hänmänsynttävää.png
158KB, 666x607px
>>8865841
Fuck no.
>>
the problem becomes trivial once the solver comes to the realization that B is actually a representation of the Earth, which is flat. Therefore, dividing A by two is as simple as aligning the flat part of B to the centroid of A, or when x = 0.
>>
>>8865841
That very first line...
x=a+b... means there's no intersection...
Shouldn't the area of intersection be 0 then?
>>
>>8865690
Not sure if this will work, but i'm tired, i'll try it later
I make a triangle with the circles inscribed in it, then I find the area of the missing gaps (should be 3 different ones, 5 total), then the sum of the gaps+circles-Area=area of triangle
>>
>>8865841
be honest anon. how long did it take you to type all that up?
>>
The solution is here:

http://mathworld.wolfram.com/Circle-CircleIntersection.html
>>
>>8865928
Oops, looks like just using RegionMeasure without any dimension specification caused it to think I wanted the 1-dimensional measure of the single point of intersection, which of course is 1.

Here's the actual area of the intersection, though it might be presented more simple here >>8867255
[eqn]
\begin{cases}
\pi a^2 & a-b+x<0 \\
\frac{a^4+2 \pi b^2 x \sqrt{b^2-\frac{\left(-a^2+b^2+x^2\right)^2}{4 x^2}}-2 a^2 b^2-2 a^2 x^2-4 b^2 x \sqrt{b^2-\frac{\left(-a^2+b^2+x^2\right)^2}{4 x^2}} \tan ^{-1}\left(\frac{-a^2+b^2+x^2}{\sqrt{-a^4+2 a^2 \left(b^2+x^2\right)-\left(b^2-x^2\right)^2}}\right)+\pi a^2 \sqrt{-a^4+2 a^2 b^2+2 a^2 x^2-b^4+2 b^2 x^2-x^4}-2 a^2 \sqrt{-a^4+2 a^2 b^2+2 a^2 x^2-b^4+2 b^2 x^2-x^4} \tan ^{-1}\left(\frac{a^2-b^2+x^2}{\sqrt{-a^4+2 a^2 \left(b^2+x^2\right)-\left(b^2-x^2\right)^2}}\right)+b^4-2 b^2 x^2+x^4}{2 \sqrt{-a^4+2 a^2 b^2+2 a^2 x^2-b^4+2 b^2 x^2-x^4}} & a-b+x>0\land a+b-x>0
\end{cases}
[/eqn]

>>8865928
0 seconds.
[math]\texttt{% // TeXForm // CopyToClipboard}[/math]
>>
I swear, you faggots only know how to type shit into a calculator.
>>
>>8867268
>1-dimensional
0-dimensional

>>8867274
A valid critique when one does not even pause to interpret the results of the calculation. But this isn't exactly a high-stakes situation...
>>
Here's my two cents:
pia^2<pib^2
if a=1,b=2
then:
pi<4pi
half of the area of circle with radius a is pi/2
to find the area of the unknown crescent:
pi/2+A=4pi
A=7pi/2
To find the radius of x
7pi/2=pi(r)^2
7/2=r^2
r=(7/2)^(1/2)
>>
>>8867639
now give us a general solution
>>
>>8867783
pia^2<pib^2
if a=n, b=n+o
then
pi(n)^2<pi(n^2+2no+o^2)
half of pi(n)^2 is pi(n)^2/2
to find the area of the unknown crescent
pi(n)^2/2+A=pi(n)^2+2pi(n)(o)+o^2
A=pi(n)^2/2+2pi(n)(o)+o^2
To find radius x
pi(n)^2/2+2pi(n)(o)+o^2=pix^2
n^2+2no+o^2=x^2
x=(n^2+2no+o^2)^(1/2)
(n is some positive interger, o>0)
Thread posts: 26
Thread images: 7


[Boards: 3 / a / aco / adv / an / asp / b / bant / biz / c / can / cgl / ck / cm / co / cock / d / diy / e / fa / fap / fit / fitlit / g / gd / gif / h / hc / his / hm / hr / i / ic / int / jp / k / lgbt / lit / m / mlp / mlpol / mo / mtv / mu / n / news / o / out / outsoc / p / po / pol / qa / qst / r / r9k / s / s4s / sci / soc / sp / spa / t / tg / toy / trash / trv / tv / u / v / vg / vint / vip / vp / vr / w / wg / wsg / wsr / x / y] [Search | Top | Home]

I'm aware that Imgur.com will stop allowing adult images since 15th of May. I'm taking actions to backup as much data as possible.
Read more on this topic here - https://archived.moe/talk/thread/1694/


If you need a post removed click on it's [Report] button and follow the instruction.
DMCA Content Takedown via dmca.com
All images are hosted on imgur.com.
If you like this website please support us by donating with Bitcoins at 16mKtbZiwW52BLkibtCr8jUg2KVUMTxVQ5
All trademarks and copyrights on this page are owned by their respective parties.
Images uploaded are the responsibility of the Poster. Comments are owned by the Poster.
This is a 4chan archive - all of the content originated from that site.
This means that RandomArchive shows their content, archived.
If you need information for a Poster - contact them.