A woman at a point [math] on the shore of a circular lake with radius [math] wants to arrive at the point [math] diametrically opposite [math] on the other side of the lake in the shortest possible time. She can walk at the rate of [math] and row a boat at [math]

What is the shortest amount of time it would take her to reach point [math]? hours

What is the longest amount of time it would take her to reach point [math] following a path like the path in the figure? hours