The PDE (St22 u(:t,t) 9 (gr22 u(z,t)) = 0 can be solved using D'Alembert method. That is, it has a solution of the form 'u(w,t) = (m + ct) + 1/)(m ct) . where c = Solve the PDE with the initial conditions 11, (9:, 0) = 3 sin(:1:), \"t (2,0) = em. Enter the expression for u(a;,t) in the box below using Maple syntax. u(:c,t) = Note: the expression should be in terms of a: and t , but not c