View Full Version : Help with an integral...
MathNerd
Apr2-04, 10:28 PM
Could someone please help me integrate
\int \frac { dx } { ( a + x )^2 + sin^{2} ( \pi x ) }
where a is just an arbitrary constant...
Thanks in advance...
cookiemonster
Apr2-04, 10:32 PM
Oh my. That is ugly.
What kind of evil person is making you do that?
cookiemonster
The Integrator can't do it, therefore it's impossible. (I know this isn't true, but when Mathematica can't do it I get kind of scared.)
http://integrals.wolfram.com/index.en.cgi
It just spits this out: http://integrals.wolfram.com/graphics.cgi?format=StandardForm&FontSize=Medium&expr=1/Sqrt%5B%28a%2Bx%29%5E2%20%2B%20%28Sin%5BPi%2Ax%5D% 29%5E2%5D
Maple 8 says it cannot be done.
No answer I guess.
The Integrator can't do it, therefore it's impossible. (I know this isn't true, but when Mathematica can't do it I get kind of scared.)
I can never get that to do a difficult integration when I have one. But yes this does look like a really nasty one.
Edit: I put it in and got this: http://integrals.wolfram.com/graphics.cgi?format=StandardForm&FontSize=Medium&x=24&expr=1%20/%20%28%20%28a%20%2B%20x%29%5E2%20%2B%20sin%5E2%28% 28Pi%29x%29%20%29&y=21
cookiemonster
Apr3-04, 03:59 PM
Both my version of Mathematica and the Integrator return the integral.
The first one you had, MathNerd, Mathematica could do, but this new one doesn't work out.
cookiemonster
I can never get that to do a difficult integration when I have one. But yes this does look like a really nasty one.
Edit: I put it in and got this: http://integrals.wolfram.com/graphics.cgi?format=StandardForm&FontSize=Medium&x=24&expr=1%20/%20%28%20%28a%20%2B%20x%29%5E2%20%2B%20sin%5E2%28% 28Pi%29x%29%20%29&y=21How do you get a sin^2 with no argument?
himanshu121
Apr4-04, 12:43 AM
U can calculate for certain sets of values of x where sin(pi x)=0 or 1
cookiemonster
Apr4-04, 01:12 AM
Yeah, really. The integral of a constant is a piece of cake.
cookiemonster
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