derivate of a two variable function on one point ti-nspire

Question

The image shows my problem (link)

I want to use that to do a Jacobian for a Multivariable method of aproximation. So There is a way to use that easily? or I have to put manually the partial derivatives like new functions? I'm sorry for my english.

Answer 1

Firstly, you dont have to use images here, you can easily insert code pieces. As for your problem, i didnt understand it. Im sure you already know that you can define a Jacobian matrix function of 2 variables:

j2_fun(f1,f2):=[[derivative(f1,x),derivative(f1,y)][derivative(f2,x),derivative(f2,y)]]

... and call it later with specific arguments, and evaluate for some x,y:

g1:=x^2+y^2
g2:=x^2-y^2
d2:=j2_fun(g1,g2)
d2|x=3 and y=1

So staring from here, please define more clearly what would you like to do with this.