A transverse harmonic wave on a string is described by y (x,t ) = 3.0 sin (36t + 0.018x + π/4) where x and y are in cm and t is in s. The positive direction of x is from left to right.

(a) The wave is travelling from right to left.

(b) The speed of the wave is 20m/s.

(c) Frequency of the wave is 5.7 Hz.

(d) The least distance between two successive crests in the wave is 2.5 cm.