Help with creating a surface plot

In a range variable a,b..c, b is the second value, not the increment. So 1,0.1..10 is not a valid sequence. You need 1,1.1..10.

Or, as Fred suggests, use CreateMesh.

Some additional remarks:

- You don't need to define a new function Z to use CreateMesh as Fred had done. You can use your function Is instead of Z directly in CreateMesh.

- In your approach (using the modification Richard suggested - 1.1 instead of 0.1) you may notice, that the abscissa and ordinate values are not correct. They are replaced by 0,1,2 ....

- Not recommended but possible: You may do without any program or CreateMesh and simply put "Is" in the placeholder of the 3D-plot component. You will get a division by zero error, because by default Mathcad varies both independent variables from -5 to +5 an eventually will also choose sigma=0, which throws the error. Double click the plot region and in tab "Quickplot Data" you can select suitable ranges for your variables.

Anyway, I already said that this is not recommended, as CreateMesh is easier and more comfortable to use.

R