Partial Derivative with Matrix

I see a few problems, solving of which - may - help:

1.

You have (x3)^3 in your matrix X, guess that's not what you intended...

2.

X is a matrix (1 row, 4 columns), Vectorization may only work with a vector (4 rows, 1 column). It just might help to transpose X...

3.

Try symbolic evaluation, instead of numeric, and make sure x1 through x4 are not defined when differentiating. Don't define them in the first place, and/or make Partial a function of x1 through x4.

This is done in Mathcad 11:

The last two items:

f is differentiated to X (which as a symbol, is NOT a parameter of f), so the partial derivative is 0.

Success!

Luc

---

@MrichCD wrote:

I tend to do a lot of partial differentiation in my analyses and how I currently do it is to hard code each partial to their own variable. This tends to clutter my analyses, since I deal with rather large multi-variable equations. I tried being slick today by defining a 1xn matrix (where n is the total number of variables and each element contains the variable names that I need to do partial derivatives on) and performing the partial derivatives on that matrix and vectorizing it. Mathcad doesn't flag an error, but what it's calculating isn't correct. I believe it's trying to do the differentiation on the value of the variable rather than seeing it as a variable by itself, because it always calculates the result as 0. Does anyone know how I can get mathcad to see these as variables or know I better way of going about this? I've attached an example of what I am attempting if it isn't clear in my writing. 

---

I wanted to try out your file and see if I could help out but I'm using MathCAD 15 and I cannot open mcdx files.  I think that it would be best for you to write some of your own vectorization code.  I did so for the modular arithmetic operator because the MathCAD programming team at PTC saw fit to ruin the vectorize operator in such a way that MathCAD docs created previously (in MathCAD 14 or earlier) now are erroneous when run using MathCAD 15.  I will give it some thought, but it would help if you can export your file to a MathCAD 15 doc and upload that as well.  The programming I'm, thinking of should not require that we use the same versions.  Another way you can help me help you is to upload a screenshot or a PDF printout of your MathCAD Prime doc.