Double-Angle Trig Identities

Write as a single trig function of a single angle.
 $2\sin\frac{\pi}{5}\cos\frac{\pi}{5}$  

Write as a single trig function of a single angle:
 $\cos^232\degree-\sin^232\degree$  

Write as a single trig function of a single angle:
 $\frac{2\tan140\degree}{1-\tan^2140\degree}$  

 $\sin x=\frac{12}{13}\ \ and\ \ \frac{\pi}{2}<x<\pi$  

Find the exact value of  $\sin2x$ .

 $\sin x=\frac{12}{13}\ \ and\ \ \frac{\pi}{2}<x<\pi$  

Find the exact value of  $\cos2x$ .

 $\sin x=\frac{12}{13}\ \ and\ \ \frac{\pi}{2}<x<\pi$  

Find the exact value of  $\tan2x$ .

 $\cos\theta=\frac{4}{5}\ \ and\ \ \frac{3\pi}{2}<\theta<2\pi$  

Find the exact value of  $\sin2\theta$ .

 $\cos\theta=\frac{4}{5}\ \ and\ \ \frac{3\pi}{2}<\theta<2\pi$  

Find the exact value of  $\cos2\theta$ .

 $\cos\theta=\frac{4}{5}\ \ and\ \ \frac{3\pi}{2}<\theta<2\pi$  

Find the exact value of  $\tan2\theta$ .

Check all the forms of the Double-Angle Formula for cos 2x: