Question

Each side of a square is increasing at a rate of 5 cm/s. at what rate is the area of the square increasing when the area of the square is 49 cm2? 70 cm2/s

Answer 1

This problem is solved using the chain rule. the area of the square is f(t) and the length of the side is g(t) f(t)=g(t)^2 g'(t)=5 Using the chain rule f'(t)=2*g(t)*g'(t) The value of g(t) is sqrt(49) which is 7. g'(t) is given as 5 cm/s f'(t)=2*7*5=14*5=70cm^2/s