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rElAtED rAtEs 微积分

Solution: Let V, r and h be the volume,radius and height of the tree trunk respectively. V = πr²h dV/dt = 2πrh(dr/dt) + πr²(dh/dt) = 2π×1.5×50×0.25 + π1.5²×1 = 39.75π If we use algebraic method to solve it, we ca...


On a certain clock,the minute hand is 4 in.long and the hour hand is 3 in.long.How fast is the distance between the tips of the hands changing at 4P.M? 在一个圆形的时钟上,分针长4英尺,时针长3英尺.求这两个针尖距离在四点钟的时...


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