The wavefunction of a transverse wave on a string is (x, t) = (30.0 cm) cos [(6.28 rad/m)x - (20.0 rad/s)t] Compute the (a) Frequency

The wavefunction of a transverse wave on a string is

ψ(x, t) = (30.0 cm) cos [(6.28 rad/m)x - (20.0 rad/s)t]

Compute the 

(a) Frequency

(b) Wavelength

(c) Period

(d) Amplitude,

(e) Phase velocity

(f) Direction of motion.