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gibson:teaching:fall-2013:math445:lab5 [2013/09/23 19:30] gibson |
gibson:teaching:fall-2013:math445:lab5 [2013/10/03 05:42] (current) gibson |
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| <latex> | <latex> | ||
| f\left(\begin{array}{c} x_1 \\ x_2 \end{array}}\right) = | f\left(\begin{array}{c} x_1 \\ x_2 \end{array}}\right) = | ||
| - | \left(\begin{array}{l} x_1^2 + x_2^2 - 7 \\ x_1^{-1} - x(2) \end{array} \right) | + | \left(\begin{array}{l} x_1^2 + x_2^2 - 7 \\ x_1^{-1} - x_2 \end{array} \right) |
| </latex> | </latex> | ||
| - | Use a contour plot of the norm of ''f'' over ''x(1), x(2)'' to find an | + | Use a contour plot of the norm of $f$ over $x_1, x_2$ to find an |
| initial guess for the search. | initial guess for the search. | ||
| - | **Problem 3:** Write a ''newtonsearchNd'' function that finds a zero of | + | **Bonus (10 pts):** Write a ''newtonsearchNd'' function that finds a zero of |
| an N-dimensional function ''f'' starting from the initial guess ''x''. | an N-dimensional function ''f'' starting from the initial guess ''x''. | ||
| Use this to find a zero of the nonlinear 3d function | Use this to find a zero of the nonlinear 3d function | ||
| Line 45: | Line 45: | ||
| \left(\begin{array}{l} 10(y-x) \\ x(28-z) - y \\ xy - 8/3 \; z \end{array} \right) | \left(\begin{array}{l} 10(y-x) \\ x(28-z) - y \\ xy - 8/3 \; z \end{array} \right) | ||
| </latex> | </latex> | ||
| + | |||
| + | Use the initial guess $[x,y,z] = [10, 10, 25]$. Verify your answer by applying it to the 3d function. What do you expect to get? | ||
| + | |||
| + | ** Bonus (10 points): ** | ||
| + | Give a brief explanation for the Newton's Search. Include the answers to the following questions. | ||
| + | |||
| + | ** - ** Purpose: What is the Newton's method used for? | ||
| + | |||
| + | ** - ** Method: How does it do this? (How is it related to the Taylor Series? Can you explain the equations used in the code?) | ||