| Line 21: | Line 21: | ||
! colspan="2" style="background: #eee;" | Euler's Formula and Related Equalities | ! colspan="2" style="background: #eee;" | Euler's Formula and Related Equalities | ||
|- | |- | ||
| − | | align="right" style="padding-right: 1em;" | Euler's formula || <math>e^{jw_0t}=\cos w_0t+j\sin w_0t</math> | + | | align="right" style="padding-right: 1em;" | Euler's formula || <math>e^{jw_0t}=\cos w_0t+j\sin w_0t \ </math> |
| + | |- | ||
| + | | align="right" style="padding-right: 1em;" | A really cute formula || <math>e^{j\pi}=-1 \ </math> | ||
|- | |- | ||
| align="right" style="padding-right: 1em;" | Cosine function in terms of complex exponentials|| <math>\cos\theta=\frac{e^{j\theta}+e^{-j\theta}}{2}</math> | | align="right" style="padding-right: 1em;" | Cosine function in terms of complex exponentials|| <math>\cos\theta=\frac{e^{j\theta}+e^{-j\theta}}{2}</math> | ||
Revision as of 08:47, 30 October 2009
| Complex Number Identities and Formulas | |
|---|---|
| Basic Definitions | |
| imaginary number | $ i=\sqrt{-1} \ $ |
| electrical engineers imaginary number | $ j=\sqrt{-1}\ $ |
| conjugate of a complex number | if $ z=a+jb $, for $ a,b\in {\mathbb R} $, then $ \bar{z}=a-jb $ |
| magnitude of a complex number | $ \| z \| = z \bar{z} $ |
| magnitude of a complex number | $ \| z \| = \sqrt{\left(Re(z)\right)^2+\left(Im(z)\right)^2} $ |
| magnitude of a complex number | $ \| a+jb \| = \sqrt{a^2+b^2} $, for $ a,b\in {\mathbb R} $ |
| magnitude of a complex number | $ \| r e^{j \theta} \| = r $, for $ r,\theta\in {\mathbb R} $ |
| Euler's Formula and Related Equalities | |
| Euler's formula | $ e^{jw_0t}=\cos w_0t+j\sin w_0t \ $ |
| A really cute formula | $ e^{j\pi}=-1 \ $ |
| Cosine function in terms of complex exponentials | $ \cos\theta=\frac{e^{j\theta}+e^{-j\theta}}{2} $ |
| Sine function in terms of complex exponentials | $ \sin\theta=\frac{e^{j\theta}-e^{-j\theta}}{2j} $ |
