Hi, I'm new to Maple and I'm trying to use it in some frequency domain convolutions analysis. At the moment, I'm just tying to organize my work and for this I need to perform some simple variable changes on multiple integrals.

I've started like this: 

> conv:= (x,h,t,tau) -> unapply(int(x(tau)*h(t-tau),tau),t);

> Y[1]:=omega->H(omega)*X(omega);

> with(IntegrationTools):

> Y[2]:=conv(Y[1],Y[1],omega,sigma1);