1. The problem statement, all variables and given/known data How do i find the phase between sine waves knowing the time difference between each? http://users.bigpond.net.au/exidez/sinewave.jpg Equation for the main function is 3cos(30t - Pi/2) The smaller sine wave is of the same frequency when is settles in a steady state. 2. Relevant equations i thought it was time difference * 2*Pi*f = phase difference in radians 3. The attempt at a solution 30 = 2*Pi * f -.05*30 = 1.5 radians -1.5*360/(2Pi) = -85.94 degrees MATLAB give the phase difference as -76.3995 degrees this is equivalent to -0.0444474274 difference in seconds Is this just due to rounding error??