posted by Edwin .
If the amplitudes of the two waves are 3 units and 1 unit respectively, show by the principle of superposition that the ratio of the amplitudes of the stationary wave at an antinode and node respectively 2:1
That would be the ratio of the sum of the two amplitudes (when they are in phase or, as they say, "add coherently") to the difference (when they are out of phase or "add destructively")
(3+1)/(3-1) = ?
The power ratio would be the square of that.