Answer Happy

Which of the following sets of equations represent pos- sible two-dimensional incompressible flow cases? (a) u = 2x² + y²-²y; v=³² + x(x²-4y) - (b) u=2xy-x²y; v = 2xy = y² + x² (c) u=x²1+ 2y: v=x²-yt (d) u= (2x + 4y)xt; v= -3(x + y)yt