how can I calculate the integral of a vector?

Hello dear experts, How can I calculate the Integral of a vector? for example we have a 1*100 row vector, named "a". so how can I determine the integral of this vector using MATLAB? ""∫a dt"" t limit is (-inf,inf)

thank for your attention.

[Andrei Bobrov]

a is function from t? ( a = fun(t) )