Hello,

I'm really new with this calculator (TI Nspire cx cas) and i'm trying to do a program to get new iterated values in finite element analysis method, newton raphson method, dunno if anyone know.

Basically, i give a R (Residue), and two values (theta1, theta2) and a want to get 2 new theta1 and theta2.

I've done myself the initial part of the program but now i'm stucked.

```
Define LibPub nr(r1,r2,theta1,theta2)=
Prgm
:Disp r=[[r1][r2]]
:Disp j=[[(r1,x),(r1,y)][(r2,x),(r2,y)]]
:x=theta1
:y=theta2
:Disp iteration=[[x][y]]-[j]^(-1)*r
:EndPrgm
```

Basically after i derivate de "j" matrix i dont know how to tell the program to change the x and y values on this matrix to the values i give initially.

I hope you guys understand and can help me on this,

Cumps,

João Sousa

P.S: Those weird symbols that appear are the derivate of the r1 in terms of x.