4. (14 points) Consider the point (2, 4, ") given in spherical coordinates. (a) This points lies on the surface of a sphere centered at the origin. What is the radius of the sphere? (b) Using spherical coordinates, find inequalities that describe the top half of the sphere. (c) Find the rectangular coordinates of the point. 13 ) (d) Now find the cylindrical coordinates of the point. 0 = tan"( r = 1 = 45-0