[tex]\text{In cadranul 1 (de la } 0^o \; la\; 90^o ), \text{ functia sinus este monoton crescatoare} \\ =\ \textgreater \ \;\;sin(x) \ \textless \ sin(x+1)\;\;\;\; unde\;\;\; x \;\in\;(0^o,\;90^o ) \\ =\ \textgreater \ \;\;\; sin\,3^o \ \textless \ sin\,4^o[/tex]
[tex]\text{Daca 3 si 4 nu sunt grade sexazecimale si sunt } \underline{ \italic{radiani}}, atunci: \\ \frac{\pi}{2}=\frac{3,14}{2}=1,57 \ \textless \ 3 \ \textless \ 3,14=\pi
=\ \textgreater \ \;\; 3 \;radiani \;este \;in \;cadranul \;2 \\ Functia\; sinus \; este\;pozitiva\;in\;cadranul\;2. \\ \\ \pi=3,14\ \textless \ 4\ \textless \ \frac{3\pi}{2} =\frac{3*3,14}{2}=3*1,57 = 4,71 \;\; \\ =\ \textgreater \ 4 \;radiani \;este \;in \;cadranul \;3 \\ Functia\; sinus \; este\;negativa\;in\;cadranul\;3. \\ \\ =\ \textgreater \ \;\;\;sin\,3 \ \textgreater \ 0 \ \textgreater \ sin\,4 \;\;\;=\ \textgreater \ \;\;\; sin\,3 \;radiani \ \textgreater \ sin\,4\;radiani[/tex]
