Imaginary number: Difference between revisions

From Citizendium
Jump to navigation Jump to search
imported>Jitse Niesen
(clarify antecedent (see also talk page) and remove link to real number because it doesn't explain "real part")
imported>Jitse Niesen
(revert edit of 19:31, 16 April 2007, which confused me - see talk page)
Line 1: Line 1:
In mathematics, an '''imaginary number''' is a [[complex number]] whose real part is zero.  A complex number is said to be real if the imaginary part is 0, and in all other cases it is non-real. Sometimes complex numbers whose real part is zero are called "pure imaginary numbers" to distinguish them from other complex numbers that are not real.
In mathematics, an '''imaginary number''' is a [[complex number]] that is not [[real number|real]]. The term is not generally used because complex numbers (e.g., <math>3 + 4i</math>) have two components, a real part (in this case 3), and an imaginary part (in this case 4). A complex number is said to be real if the imaginary part is 0, and in all other cases it is non-real. In most cases, when people speak of imaginary numbers, they are not referring to complex numbers which are not real, but complex numbers with the real part of 0. For clarity, such numbers are usually called ''pure imaginary''.


The terms ''real'' and ''imaginary'' are misnomers; they should not be taken literally.
The terms ''real'' and ''imaginary'' are misnomers; they should not be taken literally.

Revision as of 20:24, 24 April 2007

In mathematics, an imaginary number is a complex number that is not real. The term is not generally used because complex numbers (e.g., ) have two components, a real part (in this case 3), and an imaginary part (in this case 4). A complex number is said to be real if the imaginary part is 0, and in all other cases it is non-real. In most cases, when people speak of imaginary numbers, they are not referring to complex numbers which are not real, but complex numbers with the real part of 0. For clarity, such numbers are usually called pure imaginary.

The terms real and imaginary are misnomers; they should not be taken literally.

For more information, see Complex number.