\[ \frac{\pi}{2}\equiv 90^\circ \]
\[ \pi\equiv 180^\circ \]
\[ \frac{3}{2}\pi\equiv 270^\circ \]
\[ 2\pi\equiv 360^\circ \]
Rechtwinkliges Dreieck (grün)
\( \sin{\alpha}=\frac{\textrm{Gegenkathete}}{\textrm{Hypotenuse}} \)
\( =\frac{y}{r} \)
\( =\frac{y}{1} \)
\( =y \)
\( \cos{\alpha}=\frac{\textrm{Ankathete}}{\textrm{Hypotenuse}} \)
\( =\frac{x}{r}=\frac{x}{1}=x \)
Sinus/Cosinus Werte
\[
\begin{eqnarray}
\sin{0^\circ} &=& \sin{0} &=& \frac{1}{2}\sqrt{0} &=& 0 &=& \cos{90^\circ}\\
\sin{30^\circ} &=& \sin{\frac{\pi}{6}} &=& \frac{1}{2}\sqrt{1} &=&\frac{1}{2} &=& \cos{60^\circ}\\
\sin{45^\circ} &=& \sin{\frac{\pi}{4}} &=& \frac{1}{2}\sqrt{2} &=& 0.707\ldots &=& \cos{45^\circ} \\
\sin{60^\circ} &=& \sin{\frac{\pi}{3}} &=& \frac{1}{2}\sqrt{3} &=& 0.866\ldots &=& \cos{30^\circ}\\
\sin{90^\circ} &=& \sin{\frac{\pi}{2}} &=& \frac{1}{2}\sqrt{4} &=& 1 &=& \cos{0^\circ}\\
\end{eqnarray}
\]
\[ \sin{\alpha} = \cos{(90^\circ-\alpha)} \]