Standing wave can be represented as a product of two periodic functions (spatial and tem- poral). Consider the following superpositions of waves: VA(x, t) = A sin(kz wt) + 2A sin(kz + wt) VB(r, t) = A sin(kr wt) + A cos(kr + wt) vc(z,t) = Asin(kr wt) + Asin(kr + 2wt) Does either of them (A, VB and/or c) correspond to a standing wave? Use trigonometric identities to combine the terms and evaluate the results. Show the results together with a final answer (yes/no).