MATLAB: How to integrate this function

integration

t=linespace(0:0.02:2001)

t=(0:dt:T)

B data has 2002 points

How to solve this equation in matlab,

T = ...;
dt = T/(numel(B)-1);
t = linspace(dt,T-dt,numel(B)-1);
dB = diff(B);
value = trapz(t,dB.^2)

syms B(t)
f=1000;
T=1/f;
fun=((diff(B,t).^2))==0;
B=dsolve(fun);
Q=integral(matlabFunction(B),0,T);

use the trapz function

source: help file