how can i start solving this problem

Newton's second law of motion gives the equation of motion for a long light flexible string, see equation (14) of Chapter 2 in our text. We found that all waves travel, but if we confine the wave cas ( er ) - 0 to a subspace of z, 0 5 : S L, then waves traveling in opposite directions in the space create a "standing wave" which appears to be going nowhere. Assuming the string is fixed with zero am- plitude at = = 0, but free to oscillate at = = In oscillate at = = L, find all the solutions of the standing wave problem. Provide a convincing physical arguement for the boundary condition at = = L. Find the phase factor for each solution assuming the oscillations began at some :