I want to calculate the following integral in Mathematica 10
$$f(x) = \frac2\pi\int_0^\infty\exp\left(-\kappa_2\frac{t^2}{2!}+\kappa_4\frac{t^4}{4!}-\dots\right)\cos\left(\kappa_1t-\kappa_3\frac{t^3}{3!}+\dots\right)\cos(xt)\mathrm dt\quad(x > 0)$$
All $\left[\kappa_i\right]$'s are given constant factors and have finite numbers.
The written codes are here:
Integrate[
Exp[((-K[[2]]/2)*(t^2)) + ((K[[4]]/(4*3*2))*(t^4))]*
Cos[(K[[1]]*t) - ((K[[3]]/(3*2))*(t^3))]*Cos[(x*t)], {t, 0,
Infinity}]/(0.5*Pi)
However, Mathematica doesn't give explicit answer. I tried it in Matlab but it doesn't work also. I am trying to solve this integral using Pade_Approximant in Mathematica but I don't know that is it possible or not? I have several questions:
- Can I solve this integral directly? Or it needs function expansions necessarily?
- Is Pade_Approximant best expansion method for solve this?
- One of the questions is that exponential and cos function around what point(s) must be expanded?
- Is Maple better software for solving this problem?
Thank you for your help
For specific values of $k_i$ and $x$, Mathematica has no trouble, though you will need to tell it to use numerical rather than symbolic integration (
NIntegrate). For instance:gives me
If you are looking for a symbolic solution to the cosine transform, somebody else will have to help you, as it's not something I've tried to do with Mathematica before.
FourierCosTransformdoesn't work with your function as-is, unfortunately.