Tangent-function
    y = tan(x)
    from Wikimedia Commons
    plot-range: -2pi to 2pi
    plotted with cubic bezier-curves in several intervalls
    The bezier-controll-points are calculated to give a very accurate result.
    Accuracy is about 1^-6 units.
    
    All symbols are embedded in "Computer Modern" (TeX) font.
    Created with a plain text editor using GNU/Linux.

    about: http://commons.wikimedia.org/wiki/Image:Tangent-plot.svg
    source: http://commons.wikimedia.org/
    rights: GNU Free Documentation license,
            Creative Commons Attribution ShareAlike license