1. The problem statement, all variables and given/known data "Two waves are traveling in the same direction along a stretched string. The waves are 30.0° out of phase. Each wave has an amplitude of 4.00 cm. Find the amplitude of the resultant wave." 2. Relevant equations y(x,t) = Asin(kx - [tex]\omega[/tex]t) 3. The attempt at a solution Assuming that both waves are sinusoidal, I'm just summing up the two waves as follows: (4.00 cm)sin(kx-[tex]\omega[/tex]t) + (4.00 cm)sin(kx-[tex]\omega[/tex]t + 30) but I'm not sure how to find a numerical amplitude with this. Thanks for the help.