[tex] \\ \\ $Daca $ x\in \Big(\dfrac{3\pi}{2},2\pi\Big) \rightarrow $ cadranul IV.\\ \\ \Rightarrow \sin x\ \textless \ \ 0 \\ \\ $Ne intereseaza in radiani: $ \\ \\
\left\| \begin{array}{c} \pi \approx 3,14 \\ \\ \dfrac{3\pi}{2} \approx 4,71\\ \\ 2\pi \approx 6,28\end{array} \right| \Rightarrow \dfrac{3\pi}{2}\ \textless \ 6\ \textless \ 2\pi \Rightarrow 6\in \Big(\dfrac{3\pi}{2},2\pi\Big) \Rightarrow \sin 6 \ \textless \ 0[/tex]
