Two waves are perfectly superposed (traveling same direction), but are 90 degrees out of phase. Does this result in destructive or constructive interference, as the waves could be seen as either half anti-phase or half in-phase. For example, the first wave has an amplitude of 1. The second wave, 90 degrees out of phase with the first, has an amplitude of 2. Which of the following scenarios is true? A.) Total cancellation, as they are half anti-phase, so the wave with amplitude of 2 decreases the first wave's amplitude (of 1) by half it's magnitude, half of 2 is one, thus full cancellation. or B.) Partial constructive interference, the resultant has an amplitude of 2, b.c the second wave adds half of its magnitude to the first wave, half of 2 is 1, thus the resultant has an amplitude of 2. Which is correct? Can you provide a proof using the equations governing wave superposition? My confusion stems from the fact that 90 degrees phase difference between 2 waves can be seen as either half in phase or as half out of phase.