Re: Numerical Integration

[Stefano Mandelli]

Hi Marcin,

ah ah ah ..... good problem ! :D .... The problem is in the integration
of R(t)=\int_0^t dx e^{-x^2}\sin(at+b) , becouse you said "How can
integrate a integral function ?"
Bha !? I think .... that you can solve the problem of variable extrem
whith the Characteristic function in fact the integral: 
R(t)=\int_0^t dx e^{-x^2}\sin(at+b) = \int_0^{+\infty} e^{-x^2}\sin(at
+b) \cdot \chi_{[0,x]}(x) dx at this point i don't know if this integral
can be approximate easly whit the tipical integration code. Try and tell
how can you find a better method.

Cheers 
Stefano Mandelli






On sab, 2008-12-06 at 09:26 -0800, Marcin Ślęczka wrote:
> I'm a beginner on using the Octave. I've a problem with numerical integration
> of such a function:
> \int_0^1 dt \frac{1}{t^{3/2}}\exp[-iR(t)]\frac{1}{(1+R^2(t))^2} where
> R(t)=\int_0^t dx e^{-x^2}\sin(at+b) (tex code)
> I've no idea how to integrate this. Every help will be usefull.
> Thanks for help