Calculus (3rd Edition)

Published by W. H. Freeman
ISBN 10: 1464125260
ISBN 13: 978-1-46412-526-3

Chapter 11 - Infinite Series - 11.7 Taylor Series - Exercises - Page 589: 74

Answer

${f^{\left( 7 \right)}}\left( 0 \right) = - 720$ ${f^{\left( 8 \right)}}\left( 0 \right) = 0$

Work Step by Step

From Table 2: ${\tan ^{ - 1}}x = \mathop \sum \limits_{n = 0}^\infty \dfrac{{{{\left( { - 1} \right)}^n}{x^{2n + 1}}}}{{2n + 1}} = x - \dfrac{{{x^3}}}{3} + \dfrac{{{x^5}}}{5} - \dfrac{{{x^7}}}{7} + \cdot\cdot\cdot$, ${\ \ \ }$ converges for $\left| x \right| \le 1$. According to Maclaurin series: $f\left( x \right) = \mathop \sum \limits_{n = 0}^\infty \dfrac{{{f^{\left( n \right)}}\left( 0 \right)}}{{n!}}{x^n}$. So, $\dfrac{{{f^{\left( 7 \right)}}\left( 0 \right)}}{{7!}} = - \dfrac{1}{7}$ ${f^{\left( 7 \right)}}\left( 0 \right) = - \dfrac{{7!}}{7} = - 6! = - 720$ Since the even terms vanish, ${f^{\left( 8 \right)}}\left( 0 \right) = 0$.
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.