cos
⁡
(
θ
)


{\displaystyle \cos(\theta )} dan sin
⁡
(
θ
)


{\displaystyle \sin(\theta )} secara berurutan adalah nilai dari bagian real dan bagian imajiner dari e

i
θ




{\displaystyle e^{i\theta }} .
cos
⁡
(
θ
)


{\displaystyle \cos(\theta )} and sin
⁡
(
θ
)


{\displaystyle \sin(\theta )} are the real and imaginary part of e

i
θ




{\displaystyle e^{i\theta }} respectively.