Difference between revisions of "Exponential form"

 
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Every complex number z is the sum of a real and an imaginary component, z=a+bi.  If you consider complex numbers to be coordinates in the complex plane with the x-axis consisting of real numbers and the y-axis pure imaginary numbers, then every point z=a+bi can be graphed as (x,y)=(a,b).  We can convert z into polar form and re-write it as <math>z=r(\cos\theta+i\sin\theta)=r cis\theta</math>, where r=|z|.  By Euler's formula, which states that <math>e^{i\theta}=\cos\theta+i\sin\theta</math>, we can conveniently (yes, again!) rewrite z as <math>z=re^{i\theta}</math>, which is the general exponential form of a complex number.
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Every [[complex number]] z is the sum of a [[real]] and an [[imaginary]] component, z=a+bi.  If you consider complex numbers to be [[coordinate]]s in the [[complex plane]] with the x-axis consisting of real numbers and the y-axis pure imaginary numbers, then every point z=a+bi can be graphed as (x,y)=(a,b).  We can convert z into [[polar form]] and re-write it as <math>z=r(\cos\theta+i\sin\theta)=r cis\theta</math>, where r=|z|.  By [[Euler's formula]], which states that <math>e^{i\theta}=\cos\theta+i\sin\theta</math>, we can conveniently (yes, again!) rewrite z as <math>z=re^{i\theta}</math>, which is the general exponential form of a complex number.
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==See also==
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* [[Trigonometry]]
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*  [[Trigonometric identities]]

Revision as of 18:57, 23 June 2006

Every complex number z is the sum of a real and an imaginary component, z=a+bi. If you consider complex numbers to be coordinates in the complex plane with the x-axis consisting of real numbers and the y-axis pure imaginary numbers, then every point z=a+bi can be graphed as (x,y)=(a,b). We can convert z into polar form and re-write it as $z=r(\cos\theta+i\sin\theta)=r cis\theta$, where r=|z|. By Euler's formula, which states that $e^{i\theta}=\cos\theta+i\sin\theta$, we can conveniently (yes, again!) rewrite z as $z=re^{i\theta}$, which is the general exponential form of a complex number.

See also