A scientific calculator usually has special buttons for parentheses, trigonometric functions, exponents, inverses and pi -- among other things. A graphing calculator does even more.

The Desmos calculator is more advanced than the TI-84 or other devices, offering a friendlier interface, live graphing updates, and free access via a smartphone, tablet or any other connected device.

H. E. White, Jr., Functions with a Concave Modulus of Continuity, Proceedings of the American Mathematical Society, Vol. 42, No. 1 (Jan., 1974), pp. 104-112 ...