Excel doesn't know calculus. If you want mathematical integration or
differentiation, then you should consider something like Mathematica or
Maple. If you want numerical approximations to integration or
differentiation, then there are various approaches given in Abramowitz
and Stegun's "Handbook of Mathematical Functions" or discussed in most
books on numerical analysis. Alternately, you could do a Google search
on Simpson's Rule, Trapezoidal Rule, Quadrature, etc.
Jerry
