An Introduction to Polynomials Copyright Scott Storla 2015 Some Vocabulary for Polynomials Copyright Scott Storla 2015 Coefficient 3x 5 Variable term Copyright Scott Storla 2015 Constant term Definition – Polynomial A polynomial in x is a single term, or a sum of terms, where each term is a variable term or a constant. Every variable term has a coefficient, the variable x, and an exponent of x that is a natural number. Example: 2x 3 3 x 5 Notice a polynomial is a sum. You should think of 3x 2 x 4 as 3x 2 1x1 4 Copyright Scott Storla 2015 Special names for the number of terms. One term 3k Two terms 3k 7 monomial binomial Three terms 3k n 7 trinomial Copyright Scott Storla 2015 1. Write the polynomial as a sum with all coefficients and exponents explicit. 2. Discuss the polynomial in both general and specific terms. n 14 1n1 14 Copyright Scott Storla 2015 1. Write the polynomial as a sum with all coefficients explicit. 2. Discuss the polynomial in both general and specific terms. y 5 1y 1 5 Copyright Scott Storla 2015 The degree of a term For each variable term use the exponent to decide on the degree of the term. 8a 4 7a3 5a2 1 The degree of a polynomial The degree of the entire polynomial is the same as the degree of the term with the largest exponent. 8a 4 7a3 5a2 1 Copyright Scott Storla 2015 Standard Form The terms of the polynomial are written in decreasing order of degree from left to right. b 5 7b3 2b 2 Not in standard form 7b3 2b 2 b 5 Standard form To write a polynomial in standard form we imagine all operations are addition and all coefficients are explicit, then we use the commutative property to rearrange the terms, last we rewrite all explicit coefficients implicitly. b 5 7b3 2b 2 1b 5 7b3 2b 2 7b3 2b 2 1b 5 7b3 2b 2 b 5 Copyright Scott Storla 2015 Standard Form In practice people rearrange the terms of a polynomial “in their head”. Write each polynomial in standard form. 2 x 15 5 x 4 x 2 x 3 5 x 4 x 3 x 2 2 x 15 9 y 7 12y y 3 y 9 15 y 2 y 9 9 y 7 y 3 15 y 2 12y 7k 5 5k 7 8k 3 3k 8 6 4k 2 2k 4 3k 8 5k 7 7k 5 2k 4 8k 3 4k 2 6 Copyright Scott Storla 2015 1. Write the polynomial in standard form 2. Discuss the polynomial in general terms. 3. Discuss the polynomial term by term. 3 2x 2 x 2x 2 x 3 15 15y 3 15 y 3 15 6n 5 5n 6 4n 5 6n 2 5n 6 6n 5 6n 2 4n 5 Copyright Scott Storla 2015 1. Write the polynomial in standard form 2. Discuss the polynomial in general terms. 3. Discuss the polynomial term by term. 7k 5 5k 7 8k 3 3k 8 6 4k 2 2k 4 3k 8 5k 7 7k 5 2k 4 8k 3 4k 2 6 Copyright Scott Storla 2015 Multivariable or “mixed” terms With multivariable terms the degree of the term is the sum of the individual exponents. We don’t actually add the exponents. ab A second degree term 2 xy 4 3 x 2 y 3 z2 A fifth degree term A seventh degree term Copyright Scott Storla 2015 Multivariable or “mixed” terms For standard form, terms of equal degree can be written in any order but often decisions are made using alphabetical order. b 2a is often rewritten ab 2 but a 2 b is left alone. 2y 2 2 x 2 is usually rewritten 2 x 2 2 y 2 Even though 7 xy and 5 x 2 are both second degree terms, they are usually written in the order 5 x 2 7 xy . Copyright Scott Storla 2015 1. Write the polynomial in standard form 2. Discuss the polynomial in general terms. 3. Discuss the polynomial term by term. 3 xy 2 2 x 2 y x 2 y 2 x 2 y 2 2 x 2 y 3 xy 2 7ab 2 2a3 5a 2 b b3 2a3 5a 2 b 7ab 2 b3 12 j 2 k 2 2 jk 15k 4 15k 4 12 j 2 k 2 jk 2 Copyright Scott Storla 2015 Some Vocabulary for Polynomials Copyright Scott Storla 2015 Adding and Subtracting Polynomials Copyright Scott Storla 2015 Only like terms can be added or subtracted. Terms are like if, in general, they’re counting the same sized unit. Copyright Scott Storla 2015 Like Polynomial Terms Polynomial terms in one variable are like if the variable has the same exponent. Constant terms are also considered like. 6 y , 11y 6c 5 , 11c 5 6k 2 , 11k Are like terms Are like terms Are not like terms Copyright Scott Storla 2015 Decide on the like terms t 5 t3 7 t 4 x 2 2 x 2 7 x x 2 1 12 y 8 y 3 7 y 2 y 3 2 5 k 3 4k 1 k 2 Copyright Scott Storla 2015 Simplify 4 x 2 3 x 3 4 x 3 2x 2 2x 3 2x 2 4 Copyright Scott Storla 2015 Simplify 4x 3 4 x 2 5x 1 6 y y 9 4 2 5 y 0y 3 3 3 x 3 4 x x 11 7 x 8 x 0 x Copyright Scott Storla 2015 Simplify 4x 2 3 4 x 2 2 5x 2 1 6 y 3 y 2 9 4 y 2 2 5 y 3 y 3 3y 2 7 5 p7 7 p 4 4 p 4 p7 4 p7 3 p 4 6p 4 2y 2 5 y 3 4 y 2 y 9 y 3 4 y 3 6 y 2 y 3 x 3 3 x 2 4 x 2 x 11x 3 7 x 2 8 x 3 x Copyright Scott Storla 2015 Simplify 3 x 2y 4 yx yx 2 8 xy 2 x 2 y 4 xy 2 x 15 4 xy 2 xy 11x 3 xy 9 x 13 x 2y 6 y 2 x 2 xy 2 2 x 2y 2 4x 2 y 2 x 2 y xy 2 3a2b 5ba2 6a2b2 3 9b2 14b2a2 20a 2 b 2 2a 2 b 9b 2 3 4i 2 j 4i 2 j j 2 i 7i 2 j 2 7 ji 2 15i 2 j 5 j 2 i 2 2i 2 j 2 ij 2 Copyright Scott Storla 2015 Adding and Subtracting Polynomials Copyright Scott Storla 2015