@Johan159  Should be

restart;
f:=(x,y)->2*x^2+5*y^3+5:
plot(x->f(x,5), 0..10, labels=[x,z]); # The curve in 2D
plot3d(f, 0..10, 5..5, axes=normal, labels=[x,y,z]); # The same curve in 3D

@Preben Alsholm  Thank you.  In general case, you are right, but in this example there is no error, because

series(cos(x),x=0, 6) = series(cos(x),x=0, 5);
 

@Qruze  This is strange. I do not have Maple 2020 and cannot test this behavior. But this code in Maple versions 2015 - 2018 solves the example without any problems.

This issue has been discussed in detail in this thread  https://www.mapleprimes.com/questions/231640-Writing-A-Procedure-

@AHSAN  You have to do something yourself. For other questions, see the help on the  commands LinearAlgebra:-Pivot  and  LinearAlgebra:-RowOperation . 

@nm  I don't know the answer to the last question. I've never used parentheses when working with matrices.

@oggsait  Use the  legend  option for this.

@ik74  In your drawing, the center of the circle should be to the right and not to the left of the centerline.
The code for this case:

restart;
a:=2: R:=-8: z:=sqrt(R^2-(r-a+R)^2):
plot3d([[r,phi,z],[r,phi,-z]], phi=0..2*Pi, r=2..3, coords=cylindrical, scaling=constrained);

@daljit97  Sorry, I find it difficult to explain such obvious things (English is not my native language). Probably the best option for you is to take a tutorial and read about the simplest for-loops  do ... od  and conditionals  if ... fi .

This question has already been answered here  https://www.mapleprimes.com/questions/231357-Plotconvex-Or-Concave-Shell-#answer276406

@erik10  When solving nonlinear systems at specific intervals, the  DirectSearch  package can be useful.  It can be downloaded freely from the Maple Application Center. 

I think that the position of the rectangle surrounding these legends should be made one of the formal parameters of the procedure . You will specify it each time you use the procedure, depending on the situation (use  plottools:-rectangle  command). The rest can be automated in the procedure body.

@nm  You seem to have misunderstood the meaning of my answer. My code does exactly the same as  tomleslie's one or almost the same as  vv's code. I edited my answer a bit.

@priya_priti  Now the syntax is correct, but Maple simply cannot symbolically solve your system. By the way, your system has the obvious null solution: u(x)=0, v(x)=0, w(x)=0 .

@manju  In the new file, you did not do what I wrote about above.