Algebra and Trigonometry 10th Edition

Published by Cengage Learning
ISBN 10: 9781337271172
ISBN 13: 978-1-33727-117-2

Chapter 3 - 3.2 - Polynomial Functions of Higher Degree - 3.2 Exercises - Page 261: 38

Answer

a. $x=\frac{-5-\sqrt{37}}{2}$ and $x=\frac{-5+\sqrt{37}}{2}$. b. The multiplicity for zero $x=\frac{-5-\sqrt{37}}{2}$ is $1$ and is odd. The multiplicity for zero $x=\frac{-5+\sqrt{37}}{2}$ is $1$ and is odd. c. The maximum possible number of turning points is $1$. d. See graph

Work Step by Step

a. Factoring out $\frac{1}{2}$ of the polynomial: $$f(x)=\frac{1}{2}(x^2+5x-3)$$ Set $f(x)=0$: $$0=\frac{1}{2}(x^2+5x-3)$$ $$0=x^2+5x-3$$ $$x=\frac{-5\pm\sqrt{5^2-4(1)(-3)}}{2(1)}=\frac{-5\pm\sqrt{37}}{2}$$ $$x_1=\frac{-5-\sqrt{37}}{2}$$ $$x_2=\frac{-5+\sqrt{37}}{2}$$ Thus, the real zeros are $x=\frac{-5-\sqrt{37}}{2}$ and $x=\frac{-5+\sqrt{37}}{2}$. b. $$f(x)=\frac{1}{2}\left(x+\frac{-5-\sqrt{37}}{2}\right)^1\left(x-\frac{-5+\sqrt{37}}{2}\right)^1$$ From the power of the factor $\left(x+\frac{-5-\sqrt{37}}{2}\right)^1$ which is $1$, the multiplicity for zero $x=\frac{-5-\sqrt{37}}{2}$ is $1$ and is odd. From the power of the factor $\left(x-\frac{-5+\sqrt{37}}{2}\right)^1$ which is $1$, the multiplicity for zero $x=\frac{-5+\sqrt{37}}{2}$ is $1$ and is odd. c. Since the degree of the polynomial $\frac{1}{2}x^2+\frac{5}{2}x-\frac{3}{2}$ is $2$, the maximum possible number of turning points is: $$n-1=2-1=1$$ d. The graph of the function is as shown and it shows the zeros are $x=\frac{-5-\sqrt{37}}{2}$ and $x=\frac{-5+\sqrt{37}}{2}$, the multiplicity of zero $x=\frac{-5-\sqrt{37}}{2}$ is odd since the graph crosses the $x$-axis and the multiplicity of zero $x=\frac{-5+\sqrt{37}}{2}$ is odd since the graph crosses also the $x$-axis, and the number of turning points is $1$.
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