The Desmos Calculator
https://www.desmos.com/

Although their content platform is still in private beta, you can get a taste of what’s to come with their free browser-based calculator! Forged from the Desmos math engine, this is the best browser-based calculator on the web. Powerful, beautiful, intuitive, and free – forever. This has been added to the tools section of Research Resources Subject Tracer™ Information Blog.