(iii) Assume, .
Upon differentiating with respect to and applying Leibnitz product rule to get,
Therefore, .
(iv) Assume, .
Upon differentiating with respect to and applying Leibnitz product rule to get,
Therefore, .
(iii) Assume, .
Upon differentiating with respect to and applying Leibnitz product rule to get,
Therefore, .
(iv) Assume, .
Upon differentiating with respect to and applying Leibnitz product rule to get,
Therefore, .