### The Maxima on-line user's manual

Algebra Calculator

#### Contour_plot

Function: contour_plot (<expr>, <x_range>, <y_range>, <options>, ...) It plots the contours (curves of equal value) of <expr> over the region <x_range> by <y_range>. Any additional arguments are treated the same as in `plot3d`.

This function only works when the plot format is either `gnuplot` or `gnuplot_pipes`. The additional package `implicit_plot` can also be used to plot contours and it works for any format. See `implicit_plot`.

Examples:

`          (%i1) contour_plot (x^2 + y^2, [x, -4, 4], [y, -4, 4])\$`

```          (%i1) F(x, y) := x^3 + y^2;
3    2
(%o1)                  F(x, y) := x  + y
(%i2) contour_plot (F, [u, -4, 4], [v, -4, 4])\$```

You can add any options accepted by `plot3d`; for instance, the option `legend` with a value of false, to remove the legend. Gnuplot chooses, by default, 3 contours to show. to increase the number of levels, it is necessary to specify a custom gnuplot preamble:

```          (%i1) contour_plot (u^3 + v^2, [u, -4, 4], [v, -4, 4],
(%i2) [legend,false], [gnuplot_preamble,"set cntrparam levels 12"])\$```

```(%o1)                                true
(%i2) ```

### Related Examples

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Ti:20;

q:0.75*3100;

v:2250/60;

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##### contour_plot-sqrt

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##### contour_plot

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##### contour_plot

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##### contour_plot

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