Match the equation with its graph. r(u,v)=ucos(v)i+usin(v)j+vk Determine which families of grid curves have u constant and which have v constant. u constant each grid curve is a circle of radius u in the horizontal plane z=sin(u) each grid curve is a helix the grid curves lie in the vertical plane y=(tan3(u))x each grid curve is a circle of radius (1u) in the horizontal plane z=u each grid curve is a vertically oriented circle each grid curve lies in a plane z=ky that includes the x-axis v constant the grid curves are the spiral curves each grid curve is a circle contained in the vertical plane x=sin(v) parallel to the yz-plane the vertical planes y=kx through the z-axis a straight line in the plane z=v which intersects the z-axis the grid curves lie in a horizontal plane the grid curves run vertically along the surface in the planes y=kx