Question

Calculus rate of change?_"The length L of a rectangle is

"The length L of a rectangle is decreasing at a rate of 2cm per second, and teh width W is increasing at the rate of 4cm per second. Find the rate of change of the area when L = 13cm and W = 10cm."

Can someone please explain the above and work through it, i am not understanding these types of questions.

Answer

Area = A = L W

dA/dt = L dW/dt + W dL/dt

when L = 13 cm and W = 10 cm

and dL/dt = -2 cm/s and dW/dt = 4 cm/s

dA/dt = 13(4) + 10(-2) = 52-20 = 32 cm/s

Unanswered