The expression cos 𝑥 + 𝑖 sin 𝑥 is sometimes referred to as cis(𝑥)
https://en.wikipedia.org/wiki/E_(mathematical_constant)#Complex_numbers
The expression cos 𝑥 + 𝑖 sin 𝑥 is sometimes referred to as cis(𝑥)
https://en.wikipedia.org/wiki/E_(mathematical_constant)#Complex_numbers
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