## Trigonometry (11th Edition) Clone

$tan~\frac{x}{2} = 0.5$
If $0 \lt x \lt \frac{\pi}{2}$, then the angle $x$ is in quadrant I. If $sin~x = 0.8$, then $cos~x = \sqrt{1-sin^2~x} = 0.6$ We can find the value of $tan~\frac{x}{2}$: $tan~\frac{x}{2} = \frac{sin~x}{1+cos~x}$ $tan~\frac{x}{2} = \frac{0.8}{1+0.6}$ $tan~\frac{x}{2} = \frac{0.8}{1.6}$ $tan~\frac{x}{2} = 0.5$