Meaning & use
square root of -1
The imaginary unit, written i, defined as the value that equals -1 when multiplied by itself.
See it in a sentence
Engineers use i, the square root of -1, to describe alternating current in circuits.
Complex numbers combine a real part with a multiple of the square root of -1.
A note on using this word
No real number satisfies this equation, which is why mathematicians defined a new, imaginary number to represent it.
Words with a similar meaning
imaginary uniti
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