4) A physical quantity, y(x,t), is a function of distance x and time t, and also obeys the wave equation: a²y at² and a²y əx² c². 0. where c is a

wave speed. (a) What is a general solution to this wave equation? (b) The initial conditions on the y variable is given by the functions: y(x,t=0) = cos(2x) for -π/4