There are six basic elementary functions, namely, constant function (y=c), power function (y = x n), exponential function (y = a x), logarithmic function (y=loga|x) and trigonometric function (y=sinx, y=cosx, y=tanx, y=cotx, y = tanx). Elementary function is a function composed of six basic elementary functions after four operations and finite times. Other functions are derived from elementary functions.