CAS grad() function

[Han]

(05-24-2017 08:20 PM)KeithB Wrote:  How does this work without the variable list? The example gives a "Bad Argument Value" when I delete [x y z].

Shouldn't it produce a unit vector that goes in a particular direction? How do I supply values?

And what the heck is the little +/- that appears when you hit []?

grad() is a CAS command, so make sure that you are in CAS view. As an example:

grad(x^2*y,[x,y]); //--> [ 2*x*y, x^2]

It does not return a unit vector; it returns the gradient, which is defined as

\[ [ f_{x_1}, f_{x_2} , \dotsm, f_{x_n} ] \]

where \( f \) is a function of the variables \( x_1 \) through \( x_n \), and \( f_{x_i} \) denotes the partial derivative of \( f \) with respect to \( x_i \).

The +/- just means you can add row/columns by editing that position. If you place the cursor on the +/- and press + or - you can add/remove that particular row or column.