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Example 1. Use
Newton's method to solve the nonlinear system
Solution 1.
First, enter the coordinate functions
and construct the vector function
using
Mathematica, and then find the Jacobian matrix
.
![[Graphics:../Images/BroydenMethodMod_gr_18.gif]](http://math.fullerton.edu/mathews/n2003/broydenmethod/BroydenMethodMod/Images/BroydenMethodMod_gr_18.gif)
![[Graphics:../Images/BroydenMethodMod_gr_19.gif]](http://math.fullerton.edu/mathews/n2003/broydenmethod/BroydenMethodMod/Images/BroydenMethodMod_gr_19.gif)
Second, graph the curves
and
using
Mathematica. The points of intersection are the
solutions we seek.
![[Graphics:../Images/BroydenMethodMod_gr_22.gif]](http://math.fullerton.edu/mathews/n2003/broydenmethod/BroydenMethodMod/Images/BroydenMethodMod_gr_22.gif)
![[Graphics:../Images/BroydenMethodMod_gr_23.gif]](http://math.fullerton.edu/mathews/n2003/broydenmethod/BroydenMethodMod/Images/BroydenMethodMod_gr_23.gif)
(i) Use the
Newton-Raphson method to find a numerical approximation to the
solution near
.
![[Graphics:../Images/BroydenMethodMod_gr_27.gif]](http://math.fullerton.edu/mathews/n2003/broydenmethod/BroydenMethodMod/Images/BroydenMethodMod_gr_27.gif)
Accuracy is determined by the tolerance and number of iterations. How accurate was the solution "really"?
Do you think that iteration produced the solution ? Why ?
Compare with Mathematica's built in routine.
![[Graphics:../Images/BroydenMethodMod_gr_28.gif]](http://math.fullerton.edu/mathews/n2003/broydenmethod/BroydenMethodMod/Images/BroydenMethodMod_gr_28.gif)
![[Graphics:../Images/BroydenMethodMod_gr_29.gif]](http://math.fullerton.edu/mathews/n2003/broydenmethod/BroydenMethodMod/Images/BroydenMethodMod_gr_29.gif)
Whose answer is best, ours or Mathematica's ? How can this be ? Find out how to increase the number of iterations in Mathematica's subroutine.
![[Graphics:../Images/BroydenMethodMod_gr_34.gif]](http://math.fullerton.edu/mathews/n2003/broydenmethod/BroydenMethodMod/Images/BroydenMethodMod_gr_34.gif)
![[Graphics:../Images/BroydenMethodMod_gr_35.gif]](http://math.fullerton.edu/mathews/n2003/broydenmethod/BroydenMethodMod/Images/BroydenMethodMod_gr_35.gif)
(ii) Use the
Newton-Raphson method to find a numerical approximation to the
solution near
.
![[Graphics:../Images/BroydenMethodMod_gr_38.gif]](http://math.fullerton.edu/mathews/n2003/broydenmethod/BroydenMethodMod/Images/BroydenMethodMod_gr_38.gif)
Do you think that iteration produced the solution ? Why ?
Compare with Mathematica's built in routine.
![[Graphics:../Images/BroydenMethodMod_gr_39.gif]](http://math.fullerton.edu/mathews/n2003/broydenmethod/BroydenMethodMod/Images/BroydenMethodMod_gr_39.gif)
![[Graphics:../Images/BroydenMethodMod_gr_40.gif]](http://math.fullerton.edu/mathews/n2003/broydenmethod/BroydenMethodMod/Images/BroydenMethodMod_gr_40.gif)
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