I seem to recall it is possible to change a wave's frequency, pattern, and amplitude by adding another wave to it. Is it possible to add a second wave to a Sine wave to turn it into a cosine wave of the same amplitude and how would you do this? I'm thinking if I had an amplitude 1 for the sinewave, an amplitude 2 cosine wave would wipe out the sine wave and be reduced to a cosine wave. Is there a simpler way of doing this requiring less amplitude? As a side note on waves, is there a good place/website to understand the physics behind reflection?