Compute the domain of the real-valued function $f(x) = \sqrt{1 + \sqrt{2 - \sqrt{x}}}$.
Domain: 0 <= x <= 4
The outermost sqrt( 1 + ... ) has no effect upon the domain.
The sqrt( 2 - sqrt(x) ) requires that x can be no larger than 4.
The sqrt(x) requres that x can be no smaller than 0.
