Hi, I'm having some difficulty getting the correct answer for a problem relating to wave superpositiong. Question: Two waves in one string are described by the wave functions y1 = 3.15 cos (3.65x - 1.40t) and y2 = 4.10 sin (5.05x - 2.20t) where y and x are in centimeters and t is in seconds. Calculate the superposition of the waves y1 + y2 at the points x = 1.50, t = 1.30. (Remember that the arguments of the trigonometric functions are in radians.) My answer: I simply added y1+y2, after evaluating each at the given points. ytotal=3.15cos(3.655) + 4.10sin(4.715) =-6.84 cm. -6.84, and 6.84 is not the correct answer. I then, reasoned that since sine and cosine waves are out of phase by 90 degrees, to add pi/2 to one of the functions. Which resulted in. y1=3.15cos(3.655) and y2=4.10sin(4.715 + (pi/2) ) ytotal = -2.73. This is not correct either. If anyone could help me, or point me in the right direction to how you solve the problem, it would be greatly appreciated. Thanks.