pulses

y1 =5/(a x - b t)2 + 2 and y2 =-5/(a x + b t - 6)2 + 2 where a = 4.4 m-1 and b = 4.2 s-1. A) At what time do the two cancel? Answer in units of s. B) At what point do the two waves always cancel? Answer in units of m.