6 8 Transforming Polynomial Functions 6 8 Transforming

6 -8 Transforming. Polynomial. Functions 6 -8 Transforming Warm Up Lesson Presentation Lesson Quiz Holt Algebra 22

6 -8 Transforming Polynomial Functions Warm Up Let g be the indicated transformation of f(x) = 3 x + 1. Write the rule for g. 1. horizontal translation 1 unit right g(x) = 3 x – 2 2. vertical stretch by a factor of 2 g(x) = 6 x + 2 3. horizontal compression by a factor of 4 g(x) = 12 x + 1 Holt Algebra 2

6 -8 Transforming Polynomial Functions Objective Transform polynomial functions. Holt Algebra 2

6 -8 Transforming Polynomial Functions You can perform the same transformations on polynomial functions that you performed on quadratic and linear functions. Holt Algebra 2

6 -8 Transforming Polynomial Functions Example 1 A: Translating a Polynomial Function For f(x) = x 3 – 6, write the rule for each function and sketch its graph. g(x) = f(x) – 2 g(x) = (x 3 – 6) – 2 g(x) = x 3 – 8 To graph g(x) = f(x) – 2, translate the graph of f(x) 2 units down. This is a vertical translation. Holt Algebra 2

6 -8 Transforming Polynomial Functions Example 1 B: Translating a Polynomial Function For f(x) = x 3 – 6, write the rule for each function and sketch its graph. h(x) = f(x + 3) h(x) = (x + 3)3 – 6 To graph h(x) = f(x + 3), translate the graph 3 units to the left. This is a horizontal translation. Holt Algebra 2

6 -8 Transforming Polynomial Functions Check It Out! Example 1 a For f(x) = x 3 + 4, write the rule for each function and sketch its graph. g(x) = f(x) – 5 g(x) = (x 3 + 4) – 5 g(x) = x 3 – 1 To graph g(x) = f(x) – 5, translate the graph of f(x) 5 units down. This is a vertical translation. Holt Algebra 2

6 -8 Transforming Polynomial Functions Check It Out! Example 1 b For f(x) = x 3 + 4, write the rule for each function and sketch its graph. g(x) = f(x + 2) g(x) = (x + 2)3 + 4 g(x) = x 3 + 6 x 2 + 12 x + 12 To graph g(x) = f(x + 2), translate the graph 2 units left. This is a horizontal translation. Holt Algebra 2

6 -8 Transforming Polynomial Functions Example 2 A: Reflecting Polynomial Functions Let f(x) = x 3 + 5 x 2 – 8 x + 1. Write a function g that performs each transformation. Reflect f(x) across the x-axis. g(x) = –f(x) g(x) = –(x 3 + 5 x 2 – 8 x + 1) g(x) = –x 3 – 5 x 2 + 8 x – 1 Check Graph both functions. The graph appears to be a reflection. Holt Algebra 2

6 -8 Transforming Polynomial Functions Example 2 B: Reflecting Polynomial Functions Let f(x) = x 3 + 5 x 2 – 8 x + 1. Write a function g that performs each transformation. Reflect f(x) across the y-axis. g(x) = f(–x) g(x) = (–x)3 + 5(–x)2 – 8(–x) + 1 g(x) = –x 3 + 5 x 2 + 8 x + 1 Check Graph both functions. The graph appears to be a reflection. Holt Algebra 2

6 -8 Transforming Polynomial Functions Check It Out! Example 2 a Let f(x) = x 3 – 2 x 2 – x + 2. Write a function g that performs each transformation. Reflect f(x) across the x-axis. g(x) = –f(x) g(x) = –(x 3 – 2 x 2 – x + 2) g(x) = –x 3 + 2 x 2 + x – 2 Check Graph both functions. The graph appears to be a reflection. Holt Algebra 2

6 -8 Transforming Polynomial Functions Check It Out! Example 2 b Let f(x) = x 3 – 2 x 2 – x + 2. Write a function g that performs each transformation. Reflect f(x) across the y-axis. g(x) = f(–x) g(x) = (–x)3 – 2(–x)2 – (–x) + 2 g(x) = –x 3 – 2 x 2 + x + 2 Check Graph both functions. The graph appears to be a reflection. Holt Algebra 2

6 -8 Transforming Polynomial Functions Example 3 A: Compressing and Stretching Polynomial Functions Let f(x) = 2 x 4 – 6 x 2 + 1. Graph f and g on the same coordinate plane. Describe g as a transformation of f. g(x) = 1 f(x) g(x) = 2 1 2 (2 x 4 – 6 x 2 + 1) g(x) = x 4 – 3 x 2 + 1 2 g(x) is a vertical compression of f(x). Holt Algebra 2

6 -8 Transforming Polynomial Functions Example 3 B: Compressing and Stretching Polynomial Functions Let f(x) = 2 x 4 – 6 x 2 + 1. Graph f and g on the same coordinate plane. Describe g as a transformation of f. h(x) = f( 1 x) 3 h(x) = 2( 1 x)4 – 6( 1 x)2 + 1 3 3 2 4 2 2 h(x) = 81 x – 3 x +1 g(x) is a horizontal stretch of f(x). Holt Algebra 2

6 -8 Transforming Polynomial Functions Check It Out! Example 3 a Let f(x) = 16 x 4 – 24 x 2 + 4. Graph f and g on the same coordinate plane. Describe g as a transformation of f. g(x) = 1 f(x) g(x) = 4 1 (16 x 4 4 – 24 x 2 + 4) g(x) = 4 x 4 – 6 x 2 + 1 g(x) is a vertical compression of f(x). Holt Algebra 2

6 -8 Transforming Polynomial Functions Check It Out! Example 3 b Let f(x) = 16 x 4 – 24 x 2 + 4. Graph f and g on the same coordinate plane. Describe g as a transformation of f. h(x) = f( 1 x) 2 h(x) = 16( 1 x)4 – 24( 1 x)2 + 4 2 2 h(x) = x 4 – 3 x 2 + 4 g(x) is a horizontal stretch of f(x). Holt Algebra 2

6 -8 Transforming Polynomial Functions Example 4 A: Combining Transformations Write a function that transforms f(x) = 6 x 3 – 3 in each of the following ways. Support your solution by using a graphing calculator. Compress vertically by a factor of 1 , and shift 2 units right. 3 g(x) = 1 f(x – 2) 3 g(x) = 1 (6(x – 2)3 – 3) 3 g(x) = 2(x – 2)3 – 1 Holt Algebra 2

6 -8 Transforming Polynomial Functions Example 4 B: Combining Transformations Write a function that transforms f(x) = 6 x 3 – 3 in each of the following ways. Support your solution by using a graphing calculator. Reflect across the y-axis and shift 2 units down. g(x) = f(–x) – 2 g(x) = (6(–x)3 – 3) – 2 g(x) = – 6 x 3 – 5 Holt Algebra 2

6 -8 Transforming Polynomial Functions Check It Out! Example 4 a Write a function that transforms f(x) = 8 x 3 – 2 in each of the following ways. Support your solution by using a graphing calculator. Compress vertically by a factor of 1 , and move the x 2 -intercept 3 units right. g(x) = 1 f(x – 3) 2 g(x) = 1 (8(x – 3)3 – 2 2 g(x) = 4(x – 3)3 – 1 g(x) = 4 x 3 – 36 x 2 + 108 x – 1 Holt Algebra 2

6 -8 Transforming Polynomial Functions Check It Out! Example 4 b Write a function that transforms f(x) = 6 x 3 – 3 in each of the following ways. Support your solution by using a graphing calculator. Reflect across the x-axis and move the x-intercept 4 units left. g(x) = –f(x + 4) g(x) = – 6(x + 4)3 – 3 g(x) = – 8 x 3 – 96 x 2 – 384 x – 510 Holt Algebra 2

6 -8 Transforming Polynomial Functions Example 5: Consumer Application The number of skateboards sold per month can be modeled by f(x) = 0. 1 x 3 + 0. 2 x 2 + 0. 3 x + 130, where x represents the number of months since May. Let g(x) = f(x) + 20. Find the rule for g and explain the meaning of the transformation in terms of monthly skateboard sales. Step 1 Write the new rule. The new rule is g(x) = f(x) + 20 g(x) = 0. 1 x 3 + 0. 2 x 2 + 0. 3 x + 130 + 20 g(x) = 0. 1 x 3 + 0. 2 x 2 + 0. 3 x + 150 Step 2 Interpret the transformation. The transformation represents a vertical shift 20 units up, which corresponds to an increase in sales of 20 skateboards per month. Holt Algebra 2

6 -8 Transforming Polynomial Functions Check It Out! Example 5 The number of bicycles sold per month can be modeled by f(x) = 0. 01 x 3 + 0. 7 x 2 + 0. 4 x + 120, where x represents the number of months since January. Let g(x) = f(x – 5). Find the rule for g and explain the meaning of the transformation in terms of monthly skateboard sales. Step 1 Write the new rule. The new rule is g(x) = f(x – 5). g(x) = 0. 01(x – 5)3 + 0. 7(x – 5)2 + 0. 4(x – 5) + 120 g(x) = 0. 01 x 3 + 0. 55 x 2 – 5. 85 x + 134. 25 Step 2 Interpret the transformation. The transformation represents the number of sales since March. Holt Algebra 2

6 -8 Transforming Polynomial Functions Lesson Quiz: Part I 1. For f(x) = x 3 + 5, write the rule for g(x) = f(x – 1) – 2 and sketch its graph. g(x) = (x – 1)3 + 3 Holt Algebra 2

6 -8 Transforming Polynomial Functions Lesson Quiz: Part II 2. Write a function that reflects f(x) = 2 x 3 + 1 across the x-axis and shifts it 3 units down. h(x) = – 2 x 3 – 4 3. The number of videos sold per month can be modeled by f(x) = 0. 02 x 3 + 0. 6 x 2 + 0. 2 x + 125, where x represents the number of months since July. Let g(x) = f(x) – 15. Find the rule for g and explain the meaning of the transformation in terms of monthly video sales. 0. 02 x 3 + 0. 6 x 2 + 0. 2 x + 110; vertical shift 15 units down; decrease of 15 units per month Holt Algebra 2