This is something i don't understand why other mathematical tools do so badly. Have you tried navigating the graph in a matlab plot? You have to select one tool for zoom in and another tool for zoom out and then click the graph to get a huge zoom-step that isn't even centered around where you clicked. Then another tool for moving to the correct position and another to see the values. SERIOUSLY?!!?!!!! This is a super expensive tool designed for plotting and comparing graphs and the diagram-control stinks so bad. Implementing this feature properly is one day of work. Synchronizing dimensions of axis between different diagrams is also something very important that matlab has huge difficulties with. Mathematica isn't much better in this regard even though they at least plot with anti aliasing T_T.

Related is also navigation in maps-software. Not many programs do this right even though it's so simple.

Grapher does this quite well. It comes with Mac OS X and plots various things, 2D and 3D: http://www.google.com/search?q=grapher+mac&hl=en&tbm...

It also formats the equations nicely and lets you copy them as PDF. Makes a decent formula editor for Pages (with simple formulas).