The equation for the vibration of a string, fixed at both ends vibrating in its third harmonic, is given by
y=(0.4 cm)sin[(0.314 cm−1)x]cos[(600πs−1)t].
(a) What is the frequency of vibration ? (b) What are the positions of the nodes? (c) What is the length of the string ? (d) What is the waavelength and the speed of two travelling waves that can interfere to give this vibration ?