(a) Find an expression for the intensity I(x) at the point P.(Your answer may depend on x,d, and k where k is the productof the proportionality constant and the strength of the sources).
(c) If d = 10 m find the smallest value of x which minimizesthe intensity.
(d) Somewhere between d = 5 m and d = 10 m there is a tran-sitional value of d at which the point of minimal illuminationabruptly changes. Find this value for d.d =m
17.(1 point) A woman at a pointAon the shore of a circularlake with radiusr=2 wants to arrive at the pointCdiametricallyoppositeAon the other side of the lake in the shortest possibletime. She can walk at the rate of 8mph and row a boat at 4mph.What is the shortest amount of time it would take her to reachpointC?