Apply differentiation of inverse trigonometric functions to solve for optimization problems

1. A statue 3m high is standing on a base of 4m high. If an observer's eyes are 1.5m above the ground, how far should the observer stand from the base in order that the angle subtended by the statue is maximum? 2. The base of a right triangle grows 2 ft/sec, the altitude grows 4 ft/sec. If the base and altitude are originally 10 ft and 6 ft, respectively, nd the time rate of change of the base angle when the angle is 45 degrees