Yes, that means that the function you call integral with is called with an array of values - therefore your function (the long expression) should manage that. The way you've written it you will, implicitly, call it with arrays for t - so you'll have to replace ^ (which is the matrix-power in matlab) to .^ (which is the elementwise power), and where you have t*cos(t) (or the like) you'll also have to change from matrix-multiplication (*) to element-wise multiplication (.*).
HTH
