Find the rate of change of area in respect to temperature of a rectangle.

Its a steel plate that expands when heated. I have to find that rate of change when width is 1.7cm and length is 2.9. dl/dt=1.0 x 10^-5 (this is an exponent...) and dw/dt=8.0 x 10^-6

2 answers

A = l* w
dA/dt = l*dw/dt + w*dl/dt

Plug in the values and calculate
L+W