### Conversion of Differential Forms to a manipulable symbolic expression

[Sage 5.4.1] Hi, I got the following code that does total differentiation off a Sage blog:

```
sage: x, y, z = var('x, y, z')
sage: U = CoordinatePatch((x, y, z))
sage: F = DifferentialForms(U)
sage: f = F(x^2 + y + sin(z)); f
(x^2 + y + sin(z))
sage: g = f.diff();
```~~g
~~g
cos(z)*dz + 2*x*dx + dy

How do I convert `g`

to a symbolic form where `dx`

, `dy`

, and `dz`

are also symbolic variables? I need to assign values to all variables via a for loop. Also, is it possible for `g`

to be a 3x3 matrix? Thanks much, mahlon