How do I find integral of a large function?

E = 0.5*M*u(:,3).^2 + 0.5*m*(u(:,3).^2+2*L*u(:,3).*u(:,4).*cos(u(:,2))) + ...
    0.5*k* u(:,1).^2 + m*g*L*(1-cos(u(:,2))); 

How i find integral of E(t) from 0 to 20

[Walter Roberson]

There does not appear to be any t in the expression to be integrated?

[Abdur Shishir]

This is what confused me. I was given that E function and I was told to integrate.

Answer 1

[Jan]

A function, which is constant with respect to t, is integrated by multiplying its value by (tf - ti).

A = E * (tf - ti)

Does "I was told to integrate" really implies, that you have to use "t" as variable? Maybe you should integerate over u?