Calculus: Early Transcendentals 8th Edition

Published by Cengage Learning
ISBN 10: 1285741552
ISBN 13: 978-1-28574-155-0

Chapter 7 - Review - Exercises - Page 538: 46

Answer

The given improper integral $$ \int_{0}^{1} \frac{1}{2-3 x} d x $$ is divergent.

Work Step by Step

$$ \int_{0}^{1} \frac{1}{2-3 x} d x $$ Observe that the given integral is improper because $ f(x)= \frac{1}{2-3 x}$ has the vertical asymptote $x=\frac{2}{3} $. Since the infinite discontinuity occurs at the middle of the interval $ [0,1] $ at $x = \frac{2}{3} $, we must use part (c) of Definition 3 with $ c=\frac{2}{3} $: $$ \int_{0}^{1} \frac{1}{2-3 x} d x =\int_{0}^{\frac{2}{3}} \frac{1}{2-3 x} d x + \int_{\frac{2}{3}}^{1} \frac{1}{2-3 x} d x $$ where $$ \begin{split} \int_{0}^{2 / 3} \frac{1}{2-3 x} d x & =\lim _{t \rightarrow(2 / 3)-} \int_{0}^{t} \frac{1}{2-3 x} d x \\ & =\lim _{t \rightarrow(2 / 3)^{-}}\left[-\frac{1}{3} \ln |2-3 x|\right]_{0}^{t} \\ & =-\frac{1}{3} \lim _{t \rightarrow(2 / 3)-}[\ln |2-3 t|-\ln 2] \\ & =\infty \end{split} $$ so the integral $$ \int_{0}^{2 / 3} \frac{1}{2-3 x} d x $$ is divergent , so the given improper integral $$ \int_{0}^{1} \frac{1}{2-3 x} d x $$ is divergent.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.