Fitting data with integral function

I wanted to fit my data to the following equation.

y= integration(0,infinity)[(1/Dt)exp(-Dt)cos(xt)exp(-t)dt]. D is unknown parameter I am trying to extract. Can anbody help me with code lines?

Answer 1

[Vimal Rathod]

Refering to the following links might help you addressing your issue and gain more information on it:

http://www.mathworks.com/help/curvefit/custom-nonlinear-models.html

http://www.mathworks.com/discovery/data-fitting.html