Polar Form of Complex Number/Examples/4 cis 3 pi 5^-1

Example of Polar Form of Complex Number
The complex number $4 \paren {\cos \dfrac {3 \pi} 5 + i \sin \dfrac {3 \pi} 5}$ can be expressed as:
 * $4 \paren {\cos \dfrac {3 \pi} 5 + i \sin \dfrac {3 \pi} 5} = 4 \paren {\cos 108 \degrees + i \sin 108 \degrees} = 6 \cis 108 \degrees = 6 \cis \dfrac {3 \pi} 5 = 6 e^{3 \pi / 5}$

and depicted in the complex plane as:


 * 4 cis 108.png