ALGEBRA 2 5.3 Day 1 Polynomial Functions RECALL A polynomial is an expression that is a sum of variables and exponents. Degree 0 1 2 3 4 5+ Type Constant Linear Quadratic Cubic Quartic Degree n Example 12 4𝑥 − 9 5𝑥 2 − 6𝑥 − 9 8𝑥 3 + 12𝑥 2 − 3𝑥 + 1 𝑥 2 − 4𝑥 4 + 3𝑥 Examples vary LEADING COEFFICIENT The coefficient of the first term of a polynomial in standard form is called the leading coefficient. Example Leading coefficient 12 12 4𝑥 − 9 4 5𝑥 2 − 6𝑥 − 9 5 8𝑥 3 + 12𝑥 2 − 3𝑥 + 1 8 𝑥 2 − 4𝑥 4 + 3𝑥 −4 EXAMPLE 1 State the degree and leading coefficient of each polynomial in one variable. If it is not a polynomial in one variable, explain why. a) 7𝑧 3 − 4𝑧 2 + 𝑧 b) 6𝑎3 − 4𝑎2 + 𝑎𝑏 2 c) 3𝑥 5 + 2𝑥 2 − 4 − 8𝑥 6 REAL WORLD – EXAMPLE 2 RESPIRATION The volume of air in the lungs during a 5-second respiratory cycle can be modeled by v(t) = –0.037t 3 + 0.152t 2 + 0.173t, where v is the volume in liters and t is the time in seconds. This model is an example of a polynomial function. Find the volume of air in the lungs 1.5 seconds into the respiratory cycle. EXAMPLE 3 If 𝑏 𝑚 = 2𝑚2 + 𝑚 − 1, find 𝑏 2𝑥 − 1 − 3𝑏(𝑥). Step 1: Find 𝑏 2𝑥 − 1 Step 2: Find 3𝑏(𝑥) Step 3: Now subtract step 1 and 2. YOU TRY Find g(2x + 1) – 2g(x) A. 1 B. 2x 2 + 4x – 2 C. 2x 2 + 4x + 10 D. 2x 2 – 2 if g(b) = b2 + 3. Hint: Step 1: Find 𝑔(2𝑥 + 1) Step 2: Find 2𝑔(𝑥) Step 3: Now subtract step 1 and 2. EXIT SLIP 1. Determine whether 3x3 + 2x2 – 3 is a polynomial in one variable. If so, state the degree and leading coefficient. 2. Find 𝑓 2𝑥 − 𝑓(𝑥) if 𝑓 𝑥 = 𝑥 2 + 3𝑥 − 4 ALGEBRA 2 5.3 Day 2 Polynomial Functions Zeros of Even- and Odd-Degree Functions Odd-degree functions will always have an odd number of real zeros. Even-degree functions will always have an even number of real zeros or no zeros at all. The number of turns is always one less than the degree. EXAMPLE 1 For each graph, Describe the end behavior Determine whether it represents an odd-degree or an even-degree polynomial function State the number of real zeros a) b) YOU TRY For the graph, determine whether it represents an odd-degree or an even-degree function, and state the number of real zeros. EXIT SLIP For the graph, Describe the end behavior Determine whether it represents an odd-degree or an even-degree polynomial function State the number of real zeros