In algebra, a sextic (or hexic) polynomial is a polynomial of degree six. A sextic equation is a polynomial equation of degree six—that is, an equation whose left hand side is a sextic polynomial and whose right hand side is zero. More precisely, it has the form:
where a ≠ 0 and the coefficients a, b, c, d, e, f, g may be integers, rational numbers, real numbers, complex numbers or, more generally, members of any field.
A sextic function is a function defined by a sextic polynomial. Because they have an even degree, sextic functions appear similar to quartic functions when graphed, except they may possess an additional local maximum and local minimum each. The derivative of a sextic function is a quintic function.
Since a sextic function is defined by a polynomial with even degree, it has the same infinite limit when the argument goes to positive or negative infinity. If the leading coefficient a is positive, then the function increases to positive infinity at both sides and thus the function has a global minimum. Likewise, if a is negative, the sextic function decreases to negative infinity and has a global maximum.