# Euler's identity

**Euler's identity**, or **Euler's equation**, named after Leonhard Euler, is the equation of mathematical analysis

## Quotes[edit]

**One of the most frequently mentioned equations was Euler's equation,**Respondents called it "the most profound mathematical statement ever written"; "uncanny and sublime"; "filled with cosmic beauty"; and "mind-blowing". Another asked:**"What could be more mystical than an imaginary number interacting with real numbers to produce nothing?" The equation contains nine basic concepts of mathematics — once and only once — in a single expression.**These are: e (the base of natural logarithms); the exponent operation; π; plus (or minus, depending on how you write it); multiplication; imaginary numbers; equals; one; and zero.

- Like a Shakespearean sonnet that captures the very essence of love, or a painting that brings out the beauty of the human form that is far more than just skin deep,
**Euler's equation reaches down into the very depths of existence.**- Keith Devlin, as quoted in
*Dr. Euler's Fabulous Formula : Cures Many Mathematical Ills*(2006) ISBN 978-0691118222

- Keith Devlin, as quoted in

- There is a famous formula, perhaps the most compact and famous of all formulas — developed by Euler from a discovery of de Moivre:
**It appeals equally to the mystic, the scientist, the philosopher, the mathematician.**- Edward Kasner and James R. Newman, in
*Mathematics and the Imagination*(1940)

- Edward Kasner and James R. Newman, in

- Gentlemen, that is surely true, it is absolutely paradoxical; we cannot understand it, and we don't know what it means. But we have proved it, and therefore we know it must be the truth.
- Benjamin Peirce, as quoted in notes by W. E. Byerly, published in
*Benjamin Peirce, 1809-1880 : Biographical Sketch and Bibliography*(1925) by R. C. Archibald; also in*Mathematics and the Imagination*(1940) by Edward Kasner and James Newman

- Benjamin Peirce, as quoted in notes by W. E. Byerly, published in

- For any real number x, Euler’s formula is

- Where e is fundamental constant (the base of natural logarithms) and i = √-1. If we now put x =π, we get e^(iπ) = cos π+i sin π, and since cos(π) =−1 and sin(π) = 0, this reduces to e^(iπ) =−1 so that e^(iπ) +1=0.
- David Darling, in
*The Universal Book of Mathematics: From Abracadabra to Zeno's Paradoxes*(2004), John Wiley & Sons, p. 111

- David Darling, in

- This most extraordinary equation first emerged in Leonard Euler’s
*Introductio*in 1748.- David Darling, in
*The Universal Book of Mathematics : From Abracadabra to Zeno's Paradoxes*(2004), p. 111

- David Darling, in

- Since high school I have been utterly fascinated by the “mystery” of and by the beautiful calculations that flow, seemingly without end, from complex numbers and functions of complex variables.
- Paul J. Nahin, in
*Dr. Euler's Fabulous Formula: Cures Many Mathematical Ills*(2011), Princeton University Press, p. xiii

- Paul J. Nahin, in

- -1 = e^iπ,

proves that Euler was a sly guy.

- But ζ(2)

was totally new

- But ζ(2)
- And raised respect for him sky-high.
- William C. Waterhouse, as quoted in
*Dr. Euler's Fabulous Formula : Cures Many Ills*(2011), by Paul J. Nahin, p. xiii

- William C. Waterhouse, as quoted in