A wave represented by the given equation y = a cos ( kx - ω t ) is superposed
with another wave to form a stationary wave such that the point x = 0 is a
node. The equation for the other wave is
AIIMS 1998; SCRA 1998; MP PET 2001; KCET 2001;
AIEEE 2002; UPSEAT 2004]