Find the local maxima and local minima, if any, of the following functions. Find also the local maximum and the local minimum values, as the case may be:
(i) f (x) = x3 – 6x2 + 9x + 15
(ii) g(x) = \(\frac{x}{2} + \frac{2}{x}, \) x > 0
(iii) g(x) = \(\frac{1}{x^2 + 2}\)
(iv) f(x) = \(x\sqrt {1 - x}, x > 0\)