Chapter 3 – Polynomial and Rational Functions Real Zeros of Polynomials
Example A polynomial in factored form: A polynomial in expanded form: Real Zeros of Polynomials
Theorem Real Zeros of Polynomials
Finding the Rational Zeros Real Zeros of Polynomials
Descartes'’ Rule of Signs To understand this rule we need to understand the concept of variation in sign. If P(x) is a polynomial with real coefficients, written with descending powers of x and excluding powers with a 0 coefficient, then a variation of sign occurs whenever adjacent coefficients have opposite signs Real Zeros of Polynomials
Descartes’ Rule of Signs Real Zeros of Polynomials
Example This polynomial has 3 variations in sign meaning P(x) has either 3 or 1 positive zeros. P(-x) = -5x 7 + 3x 5 – x 4 + 2x 2 – x – 3 has 4 variations in sign meaning P(x) has either 4 or 2 negative zeros Real Zeros of Polynomials
Examples – pg. 260 Find all rational zeros of the polynomial and write the polynomial in factored form Real Zeros of Polynomials
Examples – pg. 261 Find all real zeros of the polynomial. Use the quadratic formula if necessary Real Zeros of Polynomials