elementary function
In mathematics, a function built from basic operations (addition, multiplication, exponentiation, logarithms, trigonometric functions, etc.) and their compositions.
The derivative of an elementary function can be found relatively easily.
Exponential and logarithmic functions are included among elementary functions.
Special functions (e.g., gamma function, Bessel functions) are not elementary; they are defined through more complex constructions.
Compound of 初等 (elementary, primary) + 関数 (function). A calque from English 'elementary function'.