A homographic function is the quotient of two first-degree polynomial functions, through an expression in the form

\(f \left( x \right)=\dfrac {ax+b} {cx+d}\)

with *c* ≠ 0.

- When
*c*= 0, the function is reduced to a first degree polynomial function, represented by a line. - The graphic representation of a homographic function is an equilateral hyperbola.