A complex number is said to be purely imaginary if it has no real part, i.e., . The term is often used in preference to the simpler "imaginary" in situations where can in general assume complex values with nonzero real parts, but in a particular case of interest, the real part is identically zero.
Purely Imaginary Number
See alsoComplex Number, Complex Plane, Imaginary Number, Real Part
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Cite this as:
Weisstein, Eric W. "Purely Imaginary Number." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/PurelyImaginaryNumber.html