Use numerical graphing calculator with unrestricted equation entry for 2D and 3D graphing.

Graphulator
Trial
Demo
Offline
https://www.graphulator.com

Graphulator - Graphing calculator is a numerical graphing calculator for 2D and 3D graphing. Unrestricted equation entry means you don't need to solve for 'y' or 'z'. Includes metric conversions and data output. Now with numerical calculus. Graphulator is an Adobe Flash file and requires Adobe Air 3.6 or greater to operate. Documentation and updates available online