i need to take a sphere and and graph a point going around the sphere. i have the code: restart: with(plots): with(plottools): x1:=(u,v)-> sin(u*Pi)*cos(v*Pi); y1:=(u,v)-> sin(u*Pi)*sin(v*Pi); z1:=(u,v)-> cos(u*Pi); x2:=(u,v)-> 3*sin(u*Pi)*cos(v*Pi); y2:=(u,v)-> 3*sin(u*Pi)*sin(v*Pi); z2:=(u,v)-> 3*cos(u*Pi); p1:=plot3d([x1(u,v), y1(u,v),z1(u,v)] ,u=0..1,v=0..2,color=blue, axes=normal): points:={seq([x1(k/50),y1(k/50),z1(k/50)], k=0..314 )}: display(p1); pointplot3d:(points); only i get the error Error, invalid input: x1 uses a 2nd argument, v, which is missing how do i put in arguments for u & v?

i am trying to plot a moving particle on two separate sphers of different radii. i have the code: restart: > with(plots): > with(plottools): > p1:=plot3d([3*sin(u)*cos(v),3*sin(u)*sin(v),3*cos(u)], u=0..Pi, v=0..2*Pi,color=red, > style=wireframe,axes=normal,scaling=constrained): > p2:=plot3d ([2.9*sin(u)*cos(v),2.9*sin(u)*sin(v),2.9*cos(u)], u=0..Pi, v=0..2*Pi,color=blue,axes=normal,scaling=constrained): > p3:=display(p1,[seq( pointplot( { [3*sin(u)*cos(v)(k/50)(n/50),3*sin(u)*sin(v)(k/50)(n/50),3*cos(u)(k/50)(n/50)],[2.9*sin(u)*cos(v)(k/50)(n/50), 2.9*sin(u)*sin(v)(k/50)(n/50),2.9*cos(u)(k/50)(n/50) ] } ) , (k,n)=(0..314,0..314) ) ],insequence=true):