题目

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

提问时间：2020-11-03

答案

一个男人划船的速度可以达到4公里每小时,跑步的速度可以达到3公里每小时,他需要从A点（南边伸长的河岸边）出发,到达B点（河的北岸）.A到B点距离是5公里,河有4公里宽,他划船的方向是与正北有个角度,求这个人从A点到B点需要的时间与这个角度的函数关系