# RationalFunctionSign RΒΆ

- R: GcdDomain

Find the sign of a rational function around a point or infinity.

- sign: (Fraction Polynomial R, Symbol, Fraction Polynomial R, String) -> Union(Integer, failed)
`sign(f, x, a, s)`

returns the sign of`f`

as`x`

nears`a`

from the left (below) if`s`

is the string`"left"`

, or from the right (above) if`s`

is the string`"right"`

.

- sign: (Fraction Polynomial R, Symbol, OrderedCompletion Fraction Polynomial R) -> Union(Integer, failed)
`sign(f, x, a)`

returns the sign of`f`

as`x`

approaches`a`

, from both sides if`a`

is finite.

- sign: Fraction Polynomial R -> Union(Integer, failed)
`sign f`

returns the sign of`f`

if it is constant everywhere.