Ok here are my two cases: View 5065_sipetest1.mw on MapleNet or Download 5065_sipetest1.mw
View file details View 5065_sipetest2.mw on MapleNet or Download 5065_sipetest2.mw
View file details A note on case two, if you change the inert Int to int then you get the same error that you get in case one. The reason that I don't like that is, as you stated, the evaluated function has a complex part. In general it should have, but in my case I have "a" and "b" or st(t) and sz(t) always positive and real, so the integral should always be a positive real quantity. I have tried using assume to get an evaluated form that does not include an imaginary term. (yes I understand that I should get the proper answer, I just would rather have a form that won't be playing with imaginary components as numerical small numbers don't always return to zero even if they should.) Thanks again.

Thanks