The capacity C of a communication channel, such as a telephone line, to carry information depends on the ratio of the signal strength S to the noise N for some positive constant k, C = k ln(1 + S/N), suppose that the signal and noise are given as a function of time t in seconds by S = 4 + cos(4t) N = 2 + sin(2t) What is dC/dt one second after transmission started? Is the capacity increasing or decreasing at that instant?