Euler's formula

Relates the complex exponential to cosine and sine, showing that e raised to an imaginary multiple of x traces a point on the unit circle. It is used throughout complex analysis, trigonometry, and electrical engineering to convert between exponential and trigonometric forms.

e^{ix} = \cos x + i \sin x

What the symbols mean

Euler's number, the base of the natural logarithm (approximately 2.71828)
the imaginary unit, satisfying i^2 = -1
a real number, usually an angle in radians
cosine of x
sine of x

About this formula

  • FieldMathematics
  • TopicComplex analysis
  • LevelUniversity
  • Also calledEuler formula complex exponential, complex exponential trigonometric identity, Euler's identity, exponential form of complex number, cos x plus i sin x
  • SourceWikidata Q184871

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