Since we are considering axial symmetry, the displacement tangential to the surface must be radial.

According to equation 4.48, the tangential displacement at B due to an element of load at C is,

	(6.7)

Thus the radial component of this displacement is

	(6.8)

The total displacement the whole load is then,

	(6.9)

The second term in the above integral vanishes when integrated over the limits 0 to 2π.