A sinusoidal wave of amplitude 0.050m travels along a stretched string in the +x-direction with a speed of 12ms−1 and a frequency of 6.0Hz. At t=0, the point at x=0 is at its maximum positive displacement (a crest). Which equation gives the displacement y(x,t) in meters?
a) y=0.050cos(πx+12πt)
b) y=0.050cos(2πx−12πt)
c) y=0.050cos(πx−12πt)
d) y=0.050sin(πx−12πt)