How to plot tan(x) curve?

[Name]

Hi, can you tell me the right way to plot y=tan(x) curve? (with gap)

[Astronomy]

Hello,

take a look at:
http://qwt.sourceforge.net/curvescreenshots.html

and in the examples of qwt in the dir:
qwt-5.2/examples

e.g.: simple_plot is the example you re looking for. There is sin and cos, but you can easily adapt it to tangens.
There's all you need

greetz,
AP.