Imaginary Unit

The imaginary number i=sqrt(-1), i.e., the square root of -1. The imaginary unit is denoted and commonly referred to as "i." Although there are two possible square roots of any number, the square roots of a negative number cannot be distinguished until one of the two is defined as the imaginary unit, at which point +i and -i can then be distinguished. Since either choice is possible, there is no ambiguity in defining i as "the" square root of -1. In the Wolfram Language, the imaginary unit is implemented as I.

See also

Complex Number, i, Imaginary Number, Unit

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Cite this as:

Weisstein, Eric W. "Imaginary Unit." From MathWorld--A Wolfram Web Resource.

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