Error, missing operator or `;`

>    x:=(2+sin(v))*cos(u);
y:=(2+sin(v))*sin(u);
z:=cos(v);

x := (2+sin(v))*cos(u)

y := (2+sin(v))*sin(u)

z := cos(v)

>    plot3d([x,y,z], u=0..2*Pi, v=0..2*Pi, grid=[30,30], scaling=constrained, axes=boxed, title="Torus example");

[Maple Plot]

>    a:=(2+exp(-u)*sin(v))*cos(u);
b:=(2+exp(-u)*sin(v))*sin(u);
c:=u+exp(-u)*cos(v);

>    plot3d([a,b,c], u=0..2*Pi, v=0..2*Pi, grid=[30,30]);

a := (2+exp(-u)*sin(v))*cos(u)

b := (2+exp(-u)*sin(v))*sin(u)

c := u+exp(-u)*cos(v)

[Maple Plot]

>   

>    x1:=3/sqrt(2)*sin(v)*cos(u);
y1:=sqrt(3)*sin(v)*sin(u);
z1:=3*cos(v);

x1 := 3/2*2^(1/2)*sin(v)*cos(u)

y1 := 3^(1/2)*sin(v)*sin(u)

z1 := 3*cos(v)

>    plot3d([x1,y1,z1], u=0..2*Pi, v=0..Pi, grid=[30,30], scaling=constrained, axes=boxed, title="Ellipse example");

[Maple Plot]

>    f:=u->(10*Pi -u)*sin(u);
a1:=f(u)*sin(v);
b1:=f(u)*cos(v);
c1:=u;

f := proc (u) options operator, arrow; (10*Pi-u)*sin(u) end proc

a1 := (10*Pi-u)*sin(u)*sin(v)

b1 := (10*Pi-u)*sin(u)*cos(v)

c1 := u

>    plot3d([a1,b1,c1], u=0..10*Pi, v=0..2*Pi, grid=[80,80],  axes=boxed, title ="Surface of revolution about z-axis");

[Maple Plot]

>   

[Maple Plot]

>