CGPET 2016 Solved Paper

At x=0, the equation for other wave will be
−cos(ωt−kx)
Because the wave will propagate in the oppositedirection with phase difference of π
Negative sign will be used as the boundary is rigid.or
y=y1+y2
y=a[cos(kx−ωt)−cos(kx−ωt)]
At, x=0,y=0
∴y2 miust be [−a‌cos(kx+ωt)]