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Plot a function between specified limits



fplot plots a function between specified limits. The function must be of the form y = f(x), where x is a vector whose range specifies the limits, and y is a vector the same size as x and contains the function's value at the points in x (see the first example). If the function returns more than one value for a given x, then y is a matrix whose columns contain each component of f(x) (see the second example).

fplot(fun,limits) plots fun between the limits specified by limits. limits is a vector specifying the x-axis limits ([xmin xmax]), or the x- and y-axes limits, ([xmin xmax ymin ymax]).

fun must be

The function f(x) must return a row vector for each element of vector x. For example, if f(x) returns [f1(x),f2(x),f3(x)] then for input [x1;x2] the function should return the matrix

fplot(fun,limits,LineSpec) plots fun using the line specification LineSpec.

fplot(fun,limits,tol) plots fun using the relative error tolerance tol (the default is 2e-3, i.e., 0.2 percent accuracy).

fplot(fun,limits,tol,LineSpec) plots fun using the relative error tolerance tol and a line specification that determines line type, marker symbol, and color. See LineSpec for more information.

fplot(fun,limits,n) with n >= 1 plots the function with a minimum of n+1 points. The default n is 1. The maximum step size is restricted to be (1/n)*(xmax-xmin).

fplot(fun,lims,...) accepts combinations of the optional arguments tol, n, and LineSpec, in any order.

fplot(axes_handle,...) plots into the axes with handle axes_handle instead of the current axes (gca).

[X,Y] = fplot(fun,limits,...) returns the abscissas and ordinates for fun in X and Y. No plot is drawn on the screen; however, you can plot the function using plot(X,Y).


fplot uses adaptive step control to produce a representative graph, concentrating its evaluation in regions where the function's rate of change is the greatest.


Plot the hyperbolic tangent function from -2 to 2:

Create an M-file, myfun, that returns a two-column matrix:

Create a function handle pointing to myfun:

Plot the function with the statement

Addition Examples

This example passes function handles to fplot, one created from a MATLAB function and the other created from an anonymous function.

See Also

eval, ezplot, feval, LineSpec, plot

Function Plots for related functions

Plotting Mathematical Functions for more examples

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