Textbook Problem

The voltage V in a simple electrical circuit is slowly decreasing as the battery wears out. The resistance R is slowly increasing as the resistor heats up. Use Ohm’s Law, V = IR, to find how the current I is changing at the moment when R = 400 Ω, I = 0.08 A, dV/dt = −0.01 V/s, and dR/dt = 0.03 Ω/s.