Sinus

Die Definition lautet $\sin \left(x\right)={\frac {{{e}^{xi}}-{{e}^{-xi}}}{2i}},\cos(x)={\frac {{{e}^{ix}}+{{e}^{-ix}}}{2}}$ Die Additionstheoreme sind: ${\begin{aligned}&\sin(x+y)=\sin(x)\cos(y)+\cos(x)\sin(y)\\&\cos(x+y)=\cos(x)\cos(y)-\sin(x)\cos(y)\\\end{aligned}}$