### Plotting from an analytic function expression

#### Plot in cartesian coordinate system

``````

In [1]:

require 'gnuplotrb'
include GnuplotRB

cartesian = Plot.new(
['x*sin(x)', with: 'lines', lt: { rgb: 'blue', lw: 3 }],
xrange: -10..10,
title: 'Math function example',
ylabel: 'x',
xlabel: 'x*sin(x)'
)

``````
``````

Out[1]:

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x*sin(x)

Math function example

x*sin(x)

x*sin(x)

``````

#### Plot in polar coordinate system

``````

In [2]:

Plot.new(
['abs(sin(3*t))', with: 'filledcurves', lt: { rgb: 'red' }],
title: 'Plot in polar example',
polar: true,
samples: 500
)

``````
``````

Out[2]:

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Plot in polar example

abs(sin(3*t))

abs(sin(3*t))

``````

#### Plot from a parametric function expression

``````

In [3]:

Plot.new(
['1.5*cos(t) - cos(30*t), 1.5*sin(t) - sin(30*t)', title: 'Parametric curve', lw: 2],
title: 'Parametric plot example',
parametric: true,
samples: 1000,
xrange: -3..3,
yrange: -3..3
)

``````
``````

Out[3]:

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Parametric plot example

Parametric curve

Parametric curve

``````