Try the fastest way to create flashcards
Question

Write the given expression as an algebraic expression in x.

sin(2tan1x)\sin \left( 2 \tan ^ { -1 } x \right)

Solution

Verified
Answered 2 years ago
Answered 2 years ago
Step 1
1 of 2

Let tan1x=θ\tan^{-1} x= \theta then we obtain

x=tanθx= \tan \theta

Therefore

sin(2tan1x)=sin(2θ)\sin ( 2 \tan^{-1} x) = \sin (2 \theta)

According to the double angle formula

sin2x=2sinxcosx\color{#c34632}{\sin 2x= 2 \sin x \cos x}

we obtain

sin(2tan1x)=2sinθcosθ\sin ( 2 \tan^{-1} x) = 2 \sin \theta \cos \theta

Since tanθ=x\tan \theta=x, we obtain

sinθ=x1+x2cosθ=11+x2\begin{align*} \sin \theta &= \frac {x}{\sqrt {1+x^2}}\\ \cos \theta &= \frac {1}{\sqrt {1+x^2}} \end{align*}

By substituting sinθ\sin \theta and cosθ\cos \theta we obtain

sin(2tan1x)=2x1+x211+x2=2x1+x2\begin{align*} \sin ( 2 \tan^{-1} x) &= 2 \frac {x}{\sqrt {1+x^2}} \cdot \frac {1}{\sqrt {1+x^2}}\\ &= \frac {2x}{1+x^2} \end{align*}

The solution is

sin(2tan1x)=2x1+x2\sin ( 2 \tan^{-1} x) = \frac {2x}{1+x^2}

Create a free account to view solutions

Create a free account to view solutions

Recommended textbook solutions

College Algebra and Trigonometry 1st Edition by Donna Gerken, Julie Miller

College Algebra and Trigonometry

1st EditionISBN: 9780078035623Donna Gerken, Julie Miller
9,697 solutions
College Algebra 12th Edition by Callie Daniels, David I. Schneider, John Hornsby, Margaret L. Lial

College Algebra

12th EditionISBN: 9780134217451Callie Daniels, David I. Schneider, John Hornsby, Margaret L. Lial
6,606 solutions
Algebra and Trigonometry 4th Edition by Lothar Redlin, Stewart, Watson

Algebra and Trigonometry

4th EditionISBN: 9781305071742 (3 more)Lothar Redlin, Stewart, Watson
11,357 solutions
College Algebra and Trigonometry 7th Edition by Richard D. Nation, Richard N. Aufmann, Vernon C. Barker

College Algebra and Trigonometry

7th EditionISBN: 9781439048603Richard D. Nation, Richard N. Aufmann, Vernon C. Barker
7,752 solutions

More related questions

1/4

1/7