英语翻译
A man can row at 4 km/h,and run at 3 km/h.He needs to get from a point A,on the south bank of a stretch of still water,to point B on the north bank of the water.The direct distance from A to B is 5 km,and the water is 4 km wide.He starts rowing with an angle theta between North and the direction in which he rows.Find an expression for the time he will take to get from A to B,in terms of theta