Leibniz function is the most basic concept of middle school mathematics, a main line running through high school mathematics curriculum and one of the most important concepts of modern mathematics. It is the most basic mathematical language and tool to describe the relationships and laws between variables in the objective world. 1692, the German mathematician Leibniz first used the word "function". He uses "function" to represent geometric quantities that change with the curve, such as the tangent and ordinate of a point.