# Interactive mathematical webpages

### Visualization of complex functions

Real functions are often visualized by drawing their graphs. This can be done well on a sheet of paper. Since this is not possible with complex functions, we visualize them in another way. We color each point of the domain according to the phase of the function value. We describe the magnitude of the values by means of contour lines.

### The cosmic travel planner

allows to calculate travel times to cosmic destinations in a (hypothetical) spaceship accelerating or decelerating with acceleration due to gravity. It comes to some surprising results.

### The interactive exercises

allow to practice certain "manual" mathematical skills. The range of topics includes set theory, linear algebra and geometry.