Write two functions that solve nonlinear systems of equations using the Quasi$-$Newton method.

Function name: qnr$\_$nls

Inputs: three: the name of the equation $($a string$),$ a vector of starting values and a scalar allowable error $($Es$)$

Outputs: one: the value of a solution to the system of equations

Comments:

H$1$ help line

Author and creation date information

Explanations of code and variables as necessary

This function must call two separate function: the one specified by the string for function evaluations and forwdiff$\_$nls$.$m for derivative evaluations

Examples of how this should work:

$\backslash$table$[[x^2-2y^2=2xy=2$ This has $2$ solutions at $(2,1)$ and $(-2,-1).,]]$

$>>x=[0$;$0]$;

$>>$ soll$=$qnr$\_$nls$(\text{'}$my$\_$fun', $x,\mathrm{.}001$

Warning: Matrix is singular to working precision. $>$ In

qnr$\_$nls $($line $17)$ soll $=$ Inf Inf

$>>x=[10$;$10]$;