Question

surface area all edges of a cube are expanding at a rate of 6 centimeters per second. how fast is the surface area changing when each edge is (a) 2 centimeters and (b) 10 centimeters?

Answer 1

S = 6x²

dS/dt = 12x(dx/dt)

(a) dS/dt = 12(2)(6) = 144 cm²/sec

(b) dS/dt = 12(2)(10) = 240 cm²/sec