(adsbygoogle = window.adsbygoogle || []).push({}); Rate of change problem...very hard...please help!!!

1. The problem statement, all variables and given/known data

The hands on a clock are of length 5 inches(minute hand) and 4 inches(hour hand). How fast is the distance between the tips of the hands changing at 3:00?

3. The attempt at a solution

Let the coordinates of the two hands be (x1,x2) for the minute hand, and (y1,y2) for the hour hand. Then,

s(distance) = sqrt((x2-y2)^2 + (x1-y1)^2)

Also,

25=(x1)^2 + (x2)^2

16=(y1)^2 + (y2)^2

Then ds/dt = (-2(x1 - x2y1/y2)dy1/dt - 2(y1 - y2x1/x2)dx1/dt)/sqrt((x2-y2)^2+(x1-y1)^2).

But I don't know how to calculate these rates.

Please Help!!!

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# Homework Help: Rate of change problem very hard please help

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