For the vector a = ya, + 5a 2. express a in spherical coordinates, both amplitudes and directions. factor the expression and group the like unit vector terms. a. b. for the point p,= (x, yb , 2b ) ( 4,0,0), what are the corresponding spherical coordinates ph (r, p.b)? using your spherical expression for a from (a) and spherical coordinates for p from (b), evaluate the value for a (should be expressed using spherical unit vectors). d. for the point pa = (xa, ya, za) = (3,3,0), what are the corresponding spherical coordinates pa (ra. 0a.9a)? using your spherical expression for a from (a) and spherical coordinates for pa from (d), evaluate the value for a (should be expressed using spherical unit vectors) c.