1 - Consider an elastic string of length L whose ends are held fixed (u(0.t)=0, u(L,t)=0). The string is set in motion with no initial velocity (u(x, 0)=0) from an initial position u(x, 0) = f(x), where f(x) is given as follows: [Ax f(x)=AL/4 for 0xL/4 for L/4