נושא : שימוש בזהויות sin ( α − 180 ) = − s i n α ? s i n α = s i n ( 180 − α ) sin ( − α ) = − sin α s i n ( 180 − α + 180 ) = s i n ( − α ) s i n ( 360 − α ) = s i n ( − α ) sin α = sin ( α + 360 ) s i n ( − α ) = s i n ( − α + 360 ) {\displaystyle {\begin{aligned}&\sin(\alpha -180)=-sin\alpha ?\\&\color {blue}sin\alpha =sin(180-\alpha )\\&\color {blue}\sin(-\alpha )=-\sin \alpha \\&sin(180-\alpha +180)=sin(-\alpha )\\&sin(360-\alpha )=sin(-\alpha )\\&\color {blue}\sin \alpha =\sin(\alpha +360)\\&sin(-\alpha )=sin(-\alpha +360)\\\end{aligned}}}
