cis
radians ⇒ number
radians | a real. |
number | a complex. |
cis returns the value of~e^i\cdot radians, which is a complex in which the real part is equal to the cosine of radians, and the imaginary part is equal to the sine of radians.
(cis 0) ⇒ #C(1.0 0.0)