I have been trying to evaluate the following integral in PARI:
intnum(x=0, +oo, x*exp(cos(x))*sin(sin(x))/(x^2-1))
but end up with the following error
*** at top-level: ...x*exp(cos(x))*sin(sin(x))/(x^2-1))
*** ^---------
*** _/_: impossible inverse in divrr: 0.E-230.
*** Break loop: type 'break' to go back to GP prompt
How should I proceed? More generally, how should one integrate such functions, which are oscillatory but not decomposable into a product of a non-oscillating function and a sine or cosine, as in the manual?
Any suggestions or references would be appreciated.
Lucas.