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July 31, 2014

July 31, 2014

Posted by **Demetria** on Thursday, November 10, 2011 at 3:33pm.

a) find the width W at the instant that the width is decreasing at the rate of .5 meters per second

b) at what rate is the diagonal d of the rectangle changing at the instant when the width is 10 meters?

- calculus -
**Damon**, Thursday, November 10, 2011 at 4:21pmA = 200 = W * L

dL/dt = 4

W = 200/L

dW/dL = -200/L^2

dW/dt = -(200/L^2)dL/dt

if dW/dt = -.5

then

-.5 = -(200/L^2) * 4

L^2 = 1600

L = 40

W = 200/40 = 5

go through that again for W = 10 to get L, dW/dt

then

D^2 = L^2 + W^2

2 D dD/dt = 2 L dL/dt + 2 W dW/dt

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