7. Here are three pairs of waves that we can send along a string. Rank the pairs according to the amplitude of the resultant wave that would result on the string, greatest first._____ [Note:請依序排列,並加註大於、小於、或等於符號(>, <, or =)]
    Pair 1:    
y1 = (4.0 mm) sin (6πx – 12πt + 0.7π)
y2 = (4.0 mm) sin (6πx – 12πt + 0.7π)
    Pair 2:    
y1 = (4.0 mm) sin (3πx – 5πt + 0.2π)
y2 = (4.0 mm) sin (3πx – 5πt + 1.2π)
    Pair 3:    
y1 = (4.0 mm) sin (2πx – 4πt)
y2 = (4.0 mm) sin (2πx – 4πt + 0.5π)