a swimmer is at a point 500m from the closest point on a straight shoreline.she needs to reach a cottage located 1800m down shore from the closest point.if she swims at 4M/s,and walks at 6M/s,how far from the cottage should she come ashore so as to a
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a swimmer is at a point 500m from the closest point on a straight shoreline.she needs to reach a cottage located 1800m down shore from the closest point.if she swims at 4M/s,and walks at 6M/s,how far from the cottage should she come ashore so as to a
a swimmer is at a point 500m from the closest point on a straight shoreline.she needs to reach a cottage located 1800m down shore from the closest point.if she swims at 4M/s,and walks at 6M/s,how far from the cottage should she come ashore so as to arrive at the cottage in the shortest time.
a swimmer is at a point 500m from the closest point on a straight shoreline.she needs to reach a cottage located 1800m down shore from the closest point.if she swims at 4M/s,and walks at 6M/s,how far from the cottage should she come ashore so as to a
这是道几何题吧.一个游泳者距离海岸线最近的点有500m.她要去距离这个最近的点1800m的岸上的一个小屋,如果她的游泳速度是4m/s,步行速度是6m/s,那么如果她要在最短时间内到达小屋需要移动多远的距离?(也就是两点之间直线最短的问题吧)
在不同的路面上有不同的速度， 好比光线穿过两种不同的介质， 只有折射的线路最快， 那么， 如果有一点 符合这个分界点， 就是一个类似折射的问题， 折射率的比值 用在这个上面 希望能帮到