A wave composed of two sinusoidal waves of identical amplitude but different frequencies has the equation
s = 2A cos (45.0t) cos (67.0t)
where the coefficient of t is stated in rad/s.
(a) What is the lower of the two frequencies (in Hz) of the sinusoidal waves?
(b) What is the higher of the two frequencies (in Hz) of the sinusoidal waves?