Multi-variable Equations and 3-D Plots

Hello again (still Mathcad 12 user),

I’m trying to generate 3-D plots of three different equations, where the 2^nd and 3^rd use the 1^st .

Each equation is a function of two variables.

I want the 3-D plots to show the value of the equation in ‘z’ and the range of the variables in ‘x’ and ‘y’ (surface plot).

Attached are three files of three different approaches.

1. Prob 5.10.xmcd
   
   1. I was able to generate the graph of the first equation, but the second, despite simplification, returns the error message, “This value must be a scalar or an array.” The function is defined properly, as best that I can tell.
      
2. Prob 5.10a.xmcd
   
   1. This builds on a method to find a single vector driven variable given to me by Stuart Bruff.
      [I seem to not be able to get the original to work, despite copying everything required from the original file.]
      The original file name is: solve_block_problem_186_859.mcd at:
      http://communities.ptc.com/message/23151#23151
      
   2. Even though, I believe, I set the solve block up correctly, when I get to the vectorize part the following error occurs, “This value must be a function.”
      
3. Prob 5.10b.xmcd
   
   1. This uses the vector approach for the variables, but only generates results using η for η for the two variables, thus generates a single curve and not a surface.
      

How can I achieve my aim of displaying the range of possibilities as a 3-D plot for all equations?

Thank you,

MNM