I'm relative new using PStricks and I don't know exactly how to draw a tangens of y=f(x) at a given point of the curve. I know, by simple mathematics that can be done by constructing the associate differential triangle at the point, [(x,y), dx, dy]. But, I think that PStricks should have a "easy-way" to do it automatically. Please, can you help me?
Pstricks consist of several packages. The basic on is
A complete list of all available packages with a small description is given at tug.org/PStricks
To plot a function the package
Plotting a tangent of given function can easily be done be the command
Here an example of the documentation:
My answer below adds the infix version to Marco Daniel's answer and provides some easy-to-customize settings as a template.