First, you do not need the inline call (that is incorrect anyway because you do not specify that the argument to it should be ‘x’). So just use a direct call to sin(x).
Unless this is a homework assignment and you are restricted in the functions you can use (that we need to know if you want our hints), I would use the trapz or cumtrapz function if you have to calculate the vector first, or the integral function if you can use the functions directly.
