A man in a river boat must get from point `A` to point `B` on the opposite bank of the river (see figure).The distance `BC=a`.The width of the river `AC=b`.At what minimum speed `u` relative to the still water should the boat travel to reach the point `B`?The velocity of flow of the river is `v_(0)`

Answer

`[(v_(0)b)/(sqrt(a^(2)+b^(2)))]`