If E1 = Eo Cos(w t) and E2 = Eo Cos(w t + theta) : a) Derive an expression for E = E1 +E2.

b) Plot E = E1 +E2 as a function of t (choose appropriate values of the unspecified quantities).

c) Plot the amplitude of E = E1 + E2 as a function of theta (choose appropriate values of the unspecified quantities).

d) What is the value of the amplitude when (1) theta =0 and (2) theta = 90 dɛypeso; (choose appropriate values of the unspecified quantities).