Other available math functions include abs, sin, cos, tan, acos, asin, atan, atan2, exp, log (natural logarithm), ceil, floor, min, max, random (takes no argument), and sqrt. The following constants are available as well: E. A Better Calculator. Desmos Graphing Calculator. Number Empire - Math Tools. Draw Function Graphs - Plotter. FooPlot: Online graphing calculator and function plotter.