Can't see where I'm going wrong here - would greatly appreciate if anyone can point it out! I've gotten the other parts of the question right, so I know that: ω = 125.66 rad/s A = 2.50 * 10-3m k = 3.49 rad/m The wave is moving in the +x direction. The general equation for the position of a particle on the wave is: y(x,t) = Acos(kx - ωt) So this means (please correct me if I'm wrong) that the transverse velocity of a particle on the wave is: Vy(x,t) = ωAsin(kx - ωt) = (125.66)((2.50 * 10-3m)sin(3.49x - 125.66t) I'm asked to find Vy at x = 1.35m, t = 0.0625s. For this I got 2.07*10-4m/s, but I'm told this is incorrect. Where am I going wrong?