1. The problem statement, all variables and given/known data Find an expression for the P-state lightwave of angular frequency w and amplitude E_0 propagating along a line in the xy-plane at 45 degrees to the x-axis and having its plane of vibration corresponding to the xy-plane. At t = 0, y = 0, and x = 0 the field is 0. 2. Relevant equations E_0x = E_0 cos(45) E_0y = E_0 sin(45) 3. The attempt at a solution I thought that it would be a sine wave given the initial conditions Thus, E = (-i + j) sqrt(2)/2 E_0 sin(k/sqrt(2) (x + y) - wt) where k = k(i + j)/sqrt(2) Or is it going to be a cosine wave?