Compute the line integral of v = (r cos2 ?) r – (r cos ? sin ?) ? + 3r ?

Compute the line integral of v = (r cos2 ?) r – (r cos ? sin ?) ? + 3r ? around the path shown in Fig. 1.50 (the points are labeled by their Cartesian coordinates). Do it either in cylindrical or in spherical coordinates. Check your answer, using Stokes' theorem.