307

$\sin x=0{,}28{,}\ \frac{\pi}{2}<x<\pi$

$\sin^2x+\cos^2x=1$
$\cos^2x=1-\sin^2x$
$\left(\cos x\right)^2=1-0{,}28^2$

$\cos x=-0{,}96$

negatiivinen koska $\frac{\pi}{2}<x<\pi$

$\tan x=\frac{\sin x}{\cos x}=\frac{0{,}28}{-0{,}96}=-0{,}3038...\approx-0{,}30$