QUESTION 6 Two traveling waves have the forms z 1 = A sin(kx - wt), 2 2 = A sin(kx + wt ) Express their superposition in the form of a standing wave. O 2A cos(kx) cost wt ) O 2A sin(kx) cos( wt ) O 2A sin(kx) sin( ct ) A sin[(kx )2 - (cut )2] O 2A cos(kx) sin( ct )