Calculus 8th Edition

Published by Cengage
ISBN 10: 1285740629
ISBN 13: 978-1-28574-062-1

Chapter 6 - Inverse Functions - 6.8 Indeterminate Forms and I'Hospital's Rule - 6.8 Exercises - Page 500: 29

Answer

$$ \lim _{x \rightarrow 0} \frac{\tanh x}{\tan x}=1 $$

Work Step by Step

$$ \lim _{x \rightarrow 0} \frac{\tanh x}{\tan x} $$ Since $$ \lim _{x \rightarrow 0}( \tanh x)=0 $$ and $$ \lim _{x \rightarrow 0}( \tan x)=0 $$ the limit is an indeterminate form of type $\frac{0}{0}$ so we can apply l’Hospital’s Rule: $$ \begin{aligned} \lim _{x \rightarrow 0} \frac{\tanh x}{\tan x} &\stackrel{\mathrm{H}}{=} \lim _{x \rightarrow 0} \frac{\operatorname{sech}^{2} x}{\sec ^{2} x} \\ &=\frac{\operatorname{sech}^{2} 0}{\sec ^{2} 0}\\ &=\frac{1}{1}\\ &=1 \end{aligned} $$
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.