Question

descarts rule of sign

Answer 1

Descartes' rule of sign
Descartes' rule of sign is used to determine the number of real zeros of a polynomial function.
It tells us that the number of positive real zeroes in a polynomial function f(x) is the same or less than by an even numbers as the number of changes in the sign of the coefficients. The number of negative real zeroes of the f(x) is the same as the number of changes in sign of the coefficients of the terms of f(-x) or less than this by an even number.