Most bored people will turn to rendering or modelling, but not Shrike. He sits and does math.
I do that all the time! Here's an interesting problem, for example:
Solve the following:
aò ³
Ö(x²-a²) dx
-aHere's the indefinite antiderivative of that: (a bit messy, as can be seen)
3/5x ³
Ö(x²-a²) - 2/5 a²x ³
Ö( [ (a²-x²)/(a²(x²-a²)) ]² ) ²F¹( { ½, 2/3 }, 3/2, x²/a² )
(²F¹ is the Gauss hypergeometric function)
Plugging in the values, this reduces to:
2/5a^(5/3)
Ö(p) G(1/3) /
G(5/6)
(
G(x) is the gamma function)
Or approximately,
»1.68261852639054581 a^(5/3)
Problem solved! w00t!
What a beautiful solution too!!
I'm working on this one right now: (should have the answer in a few days)
Find the rate at which the ratio of the surface area to the volume of an n-dimensional hypersphere changes with the number of dimensions.
This basically boils down to finding:
d(ò...ò Ö(1 + (
¶f/
¶v1)² + (
¶f/
¶v2)² ... (
¶f/
¶vn)²
) dv1 dv2 ... dvn
/ ò...ò f(v1,v2...vn) dv1 dv2 ... dvn
)/dnwhere f(v1,v2...vn)=
Ö(v1²+v2²...vn²) , v1 through vn are the independent variables (each representing one dimension) and n is the number of dimensions.
It's easier to convert it into "n-spherical" coordinates before solving (otherwise the integrals become pretty messy), so that is what I have been doing.