Answer
$-\frac{119}{169}$
Work Step by Step
Let $tan^{-1}\frac{12}{5}=y$, we have $tan(y)=\frac{12}{5}, sin(y)=\frac{12}{13},$ and
$cos(2tan^{-1}\frac{12}{5})=cos(2y)
=1-2sin^2y=1-2\times(\frac{12}{13})^2=-\frac{119}{169}$
Precalculus: Mathematics for Calculus, 7th Edition
by Stewart, James; Redlin, Lothar; Watson, Saleem
Published by
Brooks Cole
ISBN 10:
1305071751
ISBN 13:
978-1-30507-175-9
Chapter 7 - Section 7.3 - Double-Angle, Half-Angle, and Product-Sum Formulas - 7.3 Exercises - Page 561: 48
Update this answer!
You can help us out by revising, improving and updating this answer.
Update this answerAfter 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.
