Integrate using Assumptions

*To*: mathgroup at smc.vnet.net*Subject*: [mg81560] Integrate using Assumptions*From*: Art <grenander at gmail.com>*Date*: Wed, 26 Sep 2007 21:54:22 -0400 (EDT)

When I change an integrand in a way that shouldn't affect the result, mathematica is no longer able to map the integral to the built-in function. Is there any way I can help it correctly recognize the form of the function in general and in this particular case? In[1]:= Integrate[ E^Cos[theta], {theta, 0, 2Pi} ] Out[1]= 2 Pi BesselI[0, 1] but In[2]:= Integrate[ E^Cos[theta - theta0], {theta, 0, 2Pi}, Assumptions- >Element[theta0, Reals]] Cos[theta - theta0] Out[2]= Integrate[E , {theta, 0, 2 Pi}, > Assumptions -> theta0 \[Element] Reals] or even In[4]:= Integrate[E^Cos[theta-0.],{theta,0,2Pi}] Cos[0. + theta] Out[4]= Integrate[E , {theta, 0, 2 Pi}]