All edges of a cube are expanding at a rate of 3 centimeters per second. How fast is the cube's surface area changing when each edge is 10 centimeters?

expanding-a-rate

#1

All edges of a cube are expanding at a rate of 3 centimeters per second. How fast is the cube’s surface area changing when each edge is 10 centimeters?

Answer:

Surface area s= 6a^2 here a=edge
ds/dt = d/dt ×(6a^2)
= 6×2×a×(da/dt)
= 12a(da/dt)
= 12×10×3
= 360
Fast with cubes surface area changing = 360cm/sec