Dirichlet created the first modern formal definition of what mathematical concept?
Equation
Function
Derivative
Integral
Answer
A function is a relation between a set of inputs and a set of outputs where each input is related to exactly one output. Gottfried Leibniz introduced the term "function" in the 17th century, but it was not until the 19th century that Johann Peter Gustav Lejeune Dirichlet provided the first rigorous definition of the concept.
The Mathematical Legacy of Peter Gustav Lejeune Dirichlet: How Well Do You Know His Genius?