# What is the purpose of the Descartes rule of signs in determining the zeros of the polynomial function?

## What is the purpose of the Descartes rule of signs in determining the zeros of the polynomial function?

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.

## What does Descartes rule of sign not do?

Descartes’s rule of signs, in algebra, rule for determining the maximum number of positive real number solutions (roots) of a polynomial equation in one variable based on the number of times that the signs of its real number coefficients change when the terms are arranged in the canonical order (from highest power to …

How do you know how many zeros a function has?

In general, given the function, f(x), its zeros can be found by setting the function to zero. The values of x that represent the set equation are the zeroes of the function. To find the zeros of a function, find the values of x where f(x) = 0.

### Is Descartes rule of signs useful?

Descartes’ Rule of Signs is a useful help for finding the zeroes of a polynomial, assuming that you don’t have the graph to look at.

### How do you know if a root is negative or positive?

Descartes’s rule of signs says the number of positive roots is equal to changes in sign of f(x), or is less than that by an even number (so you keep subtracting 2 until you get either 1 or 0). Therefore, the previous f(x) may have 2 or 0 positive roots. Negative real roots.

Can zeros be imaginary?

Complex zeros are values of x when y equals zero, but they can’t be seen on the graph. Complex zeros consist of imaginary numbers. An imaginary number, i, is equal to the square root of negative one.

## How do you find the smallest zeros of a function?

To find the zero, set the function equal to 0. solve for x and that is your smallest zero.

What is Descartes law?

Descartes law – for two given media, the sine of the angle of incidence bears a constant relation to the sine of the angle of refraction. Synonym(s): law of refraction.

### What is Descartes’s rule of signs?

Descartes’ rule of signs. In mathematics, Descartes’ rule of signs, first described by René Descartes in his work La Géométrie, is a technique for determining the number of positive or negative real roots of a polynomial. The rule gives us an upper bound number of positive or negative roots of a polynomial. It is not a complete criterion, i.e.

### What are possible zeros?

The possible rational zeros are 1, -1, 2, -2, 3, -3, etc. My method to find the factors, was to start with 1, and check integers to see if they would divide 24 evenly. Once I got to a factor that squared was equal or greater than 24, I used another strategy.