The voltage in a electric current is 100 volts then with Ohm's law how do you find the instantaneous rate of change of I with respect to R ta a resistance of 20 ohms if R is increasing I know how to use the instantaneous formula but what is f(a)
E = IR
dE/dt = R dI/dt + I dR/dt
If E is constant, then dE/dt = 0
if R=20, then I = 5, so you can use that in the formula above. Naturally, if R is increasing, the current is decreasing.