Sign up using Facebook. The 0 tells FindRoot what value of to try first. If FindRoot does not succeed in finding a solution to the accuracy you specify within MaxIterations steps, it returns the most recent approximation to a solution that it found. They work with essentially the same arguments as FindMinimum and FindRoot except that they additionally take options, which affect the graphics functions they call to provide the plots, and they do not have the HoldAll attribute as do FindMinimum and FindRoot. The following options can be given: Please complete this field. Mathematica Stack Exchange works best with JavaScript enabled.

Give Feedback Top Thank you for your feedback! Looking around the forums I found some suggestions for similar problems – like making the definition like this: Note that this plot is nearly the same as the one produced by FindMinimumPlot with the default method for the function since the residual is the same. If you start sufficiently close to a particular root, FindRoot will give you that root. The curves for and intersect at one point. Note that in this example, all the Newton steps satisfied the Wolfe conditions, so there were no points where the function and gradient were evaluated separately from the Hessian, which is not always the case. Points at which the residual function is evaluated are shown with yellow dots. I to the starting value.

## Numerical Root Finding

Find a root of near:. FindRoot returns a list of replacements for xy…in the same form as obtained from Solve. They work with essentially the same arguments as FindMinimum and FindRoot except that they additionally take options, which affect the graphics functions they call to provide the plots, and they do not have the HoldAll attribute as do FindMinimum and FindRoot. Sign up or log in Sign up using Google.

### equation solving – Plotting results from Findroot – Mathematica Stack Exchange

Mathematica Stack Exchange works best with JavaScript enabled. Even if your equations have several solutions, FindRoot always returns the first solution it finds. If you want FindRoot to search for complex solutions, then you have to give a complex starting value.

As described earlier, the function is a residual, and the default method in FindRoot evaluates the residual and its Jacobian as shown by the yellow dots and mathemayica circles.

I’m using Mathematica 8. Note that this plot is nearly the same as the one produced by FindMinimumPlot with the default method for the function since the residual is the same. This shows in two dimensions the steps and evaluations used by FindRoot to find a root of the function starting at the point. Looking around the forums I found some suggestions for similar problems – like making the definition like this: I know this has been asked, but I cannot seem to understand the solutions.

I mean, the axis appear but nothing will be drawn on it. Please try again later.

FindRoot first localizes the values of all variables, then evaluates f with the plpt being symbolic, and then repeatedly evaluates the result numerically. If the starting point for a variable is given as a list, the values of the variable are taken to be lists with the same dimensions.

You can then apply FindRoot again, with this approximation as a starting point. If any are complex, it will also search for complex roots. Sign up or log in Sign up using Google. Please complete this field. Give Feedback Top Thank you for your feedback! Plotting results from Findroot Ask Question. FindRoot gives you a way to search for a numerical root of a function or a numerical solution to an arbitrary equation, or set of equations.

This finds a normalized eigenvector and eigenvalue. If you start sufficiently close to a particular root, FindRoot will give you that root. Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies.

What I need to know, because I have my first domiciliary test this Monday, is how to plot the output from FindRoot for a system of equations as the parameters vary.

If you specify two starting values, FindRoot uses a variant of the secant method. By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies. Post as a guest Name. How can I draw x[d]y[d]where this last two are the roots of FindRoots for different values of parameter d? Sign up using Facebook.

## Plotting Search Data

The setting for PrecisionGoal specifies the number of digits of precision to seek in the value of the position of the root. Also, please remember to accept the answer, if any, that solves your problem, by clicking the checkmark sign!

Find a solution to near:. Email Required, but never shown. If you continue to experience a problem or if you have any questions, please contact us.

The following options can be given: Points at which the function, gradient, and Hessian were all evaluated are shown by concentric green, red, and cyan circles. Note also that Newton’s method finds a different local minimum than the default method.

The calls to f with a number all work as expected, but the f in the Plot function seems to be evaluated with the symbol ‘x’ – or something and just gives a lot of error text. So I try to wrap the the code in a module so it can all be executed with just an input number, but it won’t work inside functions like Plot.

The module itself can also be simplified as shown: Please try again later. FindRoot has attribute HoldAlland effectively uses Block to localize variables.