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imaginary number
noun
: a complex number (such as 2 + 3i) in which the coefficient of the imaginary unit is not zero
called also imaginary
compare pure imaginaryExamples of imaginary number in a Sentence
Recent Examples on the Web
There’s imaginary numbers and abstract theoretical math.
—The Editors, JSTOR Daily, 24 Jan. 2024
Advanced students learn about the complex numbers, which are formed by combining the real numbers and imaginary numbers; for instance, i=√−1.
—Quanta Magazine, 27 June 2023
Eventually, the parts of the photon’s behavior described by the imaginary numbers will correspond to actual measurable properties.
—Jackie Appel, Popular Mechanics, 10 June 2023
Complex numbers have two parts, one real and one imaginary, the latter of which relates to the imaginary number i, defined as the square root of −1.
—Kevin Hartnett, Quanta Magazine, 13 Jan. 2022
Physicist Richard Feynman once predicted that number 137 defines the table’s outer limit; adding any more protons would produce an energy that could be quantified only by an imaginary number, rendering element 138 and higher impossible.
—Rebecca Coffey, Discover Magazine, 29 Nov. 2011
Because no real number x satisfies the equation x2+ 1 = 0, mathematicians built a new number system—now known as the complex numbers—by adding an imaginary number i and imposing the stipulation that i2 + 1= 0.
—Emily Riehl, Scientific American, 17 Sep. 2021
Math has many important constants that give the discipline structure, like pi and i, the imaginary number equal to the square root of -1.
—Avery Thompson, Popular Mechanics, 2 Mar. 2021
That’s an appropriate label, because an imaginary number consists of the square root of a negative number, which by definition does not exist.
—John Horgan, Scientific American, 7 Jan. 2021
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Word History
First Known Use
1798, in the meaning defined above
Dictionary Entries Near imaginary number
Cite this Entry
“Imaginary number.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/imaginary%20number. Accessed 23 Nov. 2024.
More from Merriam-Webster on imaginary number
Britannica.com: Encyclopedia article about imaginary number
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