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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.

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# Homework Help: Wave Superposition Problem

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