Sir, 1)Is it true that y = a sin(wt) is the equation of a wave pulse and y = a sin(wt – kx) is the equation of a progressive wave? I think it is true. 2)Will the following 2 waves produce stationary waves? y1 = a cos(kx – wt) y2 = a sin(kx + wt) I think the answer is No. What do you say Sir?