Help request for numeric integration and ODE solution

[SimonePirrotta]

Hi,
I met with two difficulties in Matlab:
-I have to perform the double surface integration in the field 0<x<a and 0<y<b (as with the function dblquad) but my surface is known as matrix instead of function f=f(x,y)
-then, I have to integrate a function as zdotdot(t) + a*z(t) = p(t), where again p(t) is not the function but a serie of values at different times.

Someone could help me, please?

Thanks a lot!

Simone