User:George Cox/sandbox

Using Euler's formula this can be written as

{\displaystyle z=re^{i\varphi }.\,} z=re^{i\varphi }.\, Using the cis function, this is sometimes abbreviated to

{\displaystyle z=r\operatorname {cis} \varphi .\,} z=r\operatorname {cis} \varphi .\, In angle notation, often used in electronics to represent a phasor with amplitude r and phase φ, it is written as[13]

{\displaystyle z=r\angle \varphi .\,} z=r\angle \varphi .\,