Precalculus (10th Edition)

Published by Pearson
ISBN 10: 0-32197-907-9
ISBN 13: 978-0-32197-907-0

Chapter 2 - Functions and Their Graphs - 2.4 Library of Functions; Piecewise-defined Functions - 2.4 Assess Your Understanding - Page 90: 31

Answer

(a) domain $(-\infty,\infty)$ (b) no $x$-intercept; $y$-intercept is $1$ (c) Refer to the attached image. (d) range $(-\infty,0)\cup(0,\infty)$ (e) not continuous

Work Step by Step

Based on the given piece-wise function, we have: (a) The domain is the set of all values of $x$. Thus, the domain of the given function is $(-\infty,\infty)$ since no $x$ value is excluded. (b) To find the $x$-intercepts, let $f(x)=0$ then solve for $x$: $2x=0\\ x=0$ This contradicts the definition of the given function which says $f(0)=1$, thus the function has no $x$-intercept. To find the $y$-intercepts, let $x=0$: $f(0)=1$ Thus, the $y$-intercept is $1$. (c) The graph of the function is the $y=2x$ except when $x=0$ where $f(x)=y=1$. Thus, the graph is a line with a hollow dot at $x=0$, and the point $(0, 1)$. Refer to the graph below. (d) The range of the function is the set of all $y$ values. The graph shows that the $y$ value can be any real number except $0$. Thus, the range is $(-\infty,0)\cup(0,\infty)$. (e) We can see that $f(x)$ is not continuous on its domain as there is a discontinuity at $x=0$.
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