The Imaginary Number is defined as . However, for some reason engineers and physicists prefer the symbol j to . Numbers of the form where and are Real Numbers are called Complex Numbers, and when is used to denote a Complex Number, it is sometimes (in older texts) called an ``Affix.''
The Square Root of is
The Principal Value of is
See also Complex Number, Imaginary Identity, Imaginary Number, Real Number, Surreal Number
Courant, R. and Robbins, H. What is Mathematics?: An Elementary Approach to Ideas and Methods, 2nd ed.
Oxford, England: Oxford University Press, p. 89, 1996.