Consider the upper half of the astroid described by

x^(2/3)+y^(2/3)=a^(2/3) where a>0 and |x|<(or equal to)a.

Find the area of the surface generated when this curve is revolved about thex-axis. Use symmetry. Note that the function describing the curve is not differentiable at 0.However, the surface area integral can be evaluated using methods that are known.