10.26. Calculate the gravitatiorial potential and the gravitational field intensity duc t a thin circular disk of mass M and radius R at a point P at a distance r from the center of the disk and making an an- gle 6 with the Z-axis, similar to Fig. P10.23. Assume that r> R, and expand the expression for the - potential, keping only the second-order termis in Rlr. Graph V(r) and g(r). 10.17. Considet a body that has a cylindrical symimtry with density p(r, 6) for r. < R and p = 0 for r> R. Calculate the gravitational potential at a point (7, 6) far away from th body. (Expand in powers of Rir.)