compute integral with Maxima



On Thu, 27 Nov 2008, Dan Stanger wrote

>There is a trig identity which converts 4*a*b*(sin(x)+cos(x)) to 
>sqrt(2)*4*a*b*cos(x-atan2(a,b)).
>Then the integrand can be expanded into I0(4*sqrt(2)*a*b)+ a sum 
>containing terms multiplied by cos(n*(x+atan2(a,b))
>which when integrated between 0 and 2*pi give 0.

 Could you provide more details about the integrand being 
  expanded into " I0(4*sqrt(2)*a*b)+ a sum containing 
     terms multiplied by cos(n*(x+atan2(a,b)) " ?

Ted Woollett