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| <math> \frac{s^3}{(s^2-a^2)^3}\ </math> | | <math> \frac{s^3}{(s^2-a^2)^3}\ </math> | ||
| <math> \frac{3t\ {sh}\ {at}+at^2\ {ch}\ {at}}{8a}\ </math> | | <math> \frac{3t\ {sh}\ {at}+at^2\ {ch}\ {at}}{8a}\ </math> | ||
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| <math> \frac{s^3+3a^2s}{(s^2-a^2)^3}\ </math> | | <math> \frac{s^3+3a^2s}{(s^2-a^2)^3}\ </math> | ||
| <math> \frac12t^2\ {ch}\ {at}\ </math> | | <math> \frac12t^2\ {ch}\ {at}\ </math> | ||
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| <math> \frac{1}{s^3-a^3}\ </math> | | <math> \frac{1}{s^3-a^3}\ </math> | ||
| − | | <math> \frac{e^{at/2}}{3a^2 | + | | <math> \frac{e^{at/2}}{3a^2}\ </math> |
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| align="right" style="padding-right: 1em;" | please continue | | align="right" style="padding-right: 1em;" | please continue | ||
Revision as of 19:38, 13 November 2010
There is a problem with the properties listed below. The Laplace transform is a function of a complex variable, denoted by s in all ECE courses. Now below, the Laplace transform appears to be a function of a real variable t. This is seen, for example, by the fact that the function u(t) appears in the table; now u(t) must be a function of a real variable t, because, the statement "t>0" does not make any sense when the variable t is a complex number. Also, one thing that needs to be added is the ROC in the 4th column of the properties table. Please let me know if you need a reference.-pm
Yes, I need a reference of the properties
| Laplace Transform Pairs and Properties | |||
|---|---|---|---|
| Definition | |||
| Laplace Transform | $ F(s)=\int_{-\infty}^\infty f(t) e^{-st}dt, \ s\in {\mathbb C} \ $ | ||
| Inverse Laplace Transform | add formula here | ||
| Properties of the Laplace Transform | |||
| function $ F(s) \ $ | Laplace transform $ f(t) \ $ | ROC $ R $ | |
| $ aF_1(s)+bF_2(s) \ $ | $ af_1(t)+bf_2(t) \ $ | at least $ R_1 \cap R_2 $ | |
| $ F\left( \frac{s}{a} \right) $ | $ af(at) \ $ | ||
| $ F(s-a) \ $ | $ e^{at}f(t) \ $ | ||
| $ e^{-as}F(s) \ $ | $ u(t-a) = \begin{cases} f(t-a) & t>a \\ 0 & t<a \end{cases} $ | ||
| $ sF(s)-f(0) \ $ | $ f'(t) \ $ | ||
| $ s^2F(s)-sf(0)-f'(0) \ $ | $ f''(t) \ $ | ||
| $ s^{n}F(s)-\sum_{k=1}^ns^{n-k}f^{(k)}(0) \ $ | $ f^{(n)}(t) \ $ | ||
| $ F'(s) \ $ | $ -tf(t) \ $ | ||
| $ F''(s) \ $ | $ t^2f(t) \ $ | ||
| $ F^{(n)}(s) \ $ | $ (-1)^{(ntn)}f(t) \ $ | ||
| $ \frac{F(s)}s \ $ | $ \int_{0}^{t} f(u) du \ $ | ||
| $ \frac{F(s)}{s^n} \ $ | $ \int_{0}^{t}...\int_{0}^{t}f(u)du^n = \int_{0}^{t}\frac{{(t-u)}^{n-1}}{(n-1)!} f(u)du \ $ | ||
| $ F(s)G(s) \ $ | $ \int_{0}^{t}f(u)g(t-u)du \ $ | ||
| $ \int_{s}^{\infty}F(u)du \ $ | $ \frac{f(t)}t \ $ | ||
| $ \frac1{1-e^{-sT}}\int_{0}^{T}e^{-su}f(u)du \ $ | $ f(t)=f(t+T) \ $ | ||
| $ \frac{F(\sqrt{s})}s \ $ | $ \frac{1}{\sqrt{{\pi}t}}\int_{0}^{\infty}e^{-\frac{u^2}4t}f(u)du $ | ||
| $ \frac1sF\left(\frac1s\right) \ $ | $ \int_{0}^{\infty}J_0(2\sqrt{ut})f(u)du \ $ | ||
| $ \frac1{s^{n+1}}F\left(\frac1s\right) \ $ | $ t^{\frac{n}2}\int_{0}^{\infty}u^{-\frac{n}2}J_n(2\sqrt{ut})f(u)du \ $ | ||
| $ \frac{F(s+\frac1s)}{s^2+1} \ $ | $ \int_{0}^{t}J_0(2\sqrt{u(t-u)})f(u)du \ $ | ||
| $ \frac1{2\sqrt\pi}\int_{0}^{\infty}u^{-\frac32}e^{-\frac{s^2}{4u}}F(u)du \ $ | $ f(t^2) \ $ | ||
| $ \frac{F(\ln s)}{s\ln s} \ $ | $ \int_{0}^{\infty}\frac{t^uf(u)}{\Gamma(u+1)}du \ $ | ||
| $ \frac{P(s)}{Q(s)} \ $ | $ \sum_{k=1}^N \frac{P(\alpha_k)}{Q'(\alpha_k)}e^{\alpha_kt} \ $ | ||
| $ \frac1s \ $ | $ 1 \ $ | ||
| $ \frac1{s^2} \ $ | $ t \ $ | ||
| $ \frac1{s^n}, \ n=1,2,3,... \ $ | $ \frac{t^{n-1}}{(n-1)!}, \ 0!=1 \ $ | ||
| $ \frac1{s^n}, \ n>0 \ $ | $ \frac{t^{n-1}}{\Gamma(n)} \ $ | ||
| $ \frac1{s-a}\ $ | $ e^{at}\ $ | ||
| $ \frac1{(s-a)^n}, \ n=1,2,3,...\ $ | $ \frac{t^{n-1}e^{at}}{(n-1)!}, \ 0!=1\ $ | ||
| $ \frac1{(s-a)^n}, \ n>0\ $ | $ \frac{t^{n-1}e^{at}}{\Gamma(n)}\ $ | ||
| $ \frac1{s^2+a^2}\ $ | $ \frac{\sin {at}}{a} \ $ | ||
| $ \frac{s}{s^2+a^2} \ $ | $ \cos {at} \ $ | ||
| $ \frac1{(s-b)^2+a^2}\ $ | $ \frac{e^{bt}\sin{at}}{a} \ $ | ||
| $ \frac{s-b}{(s-b)^2+a^2}\ $ | $ e^{bt}\cos{at}\ $ | ||
| $ \frac{1}{s^2-a^2} \ $ | $ \left(\frac{{sh}\ {at}}{a}\right)\ $ | ||
| $ \frac{s}{s^2-a^2}\ $ | $ {ch}\ {at}\ $ | ||
| $ \frac1{(s-b)^2-a^2}\ $ | $ \frac{e^{bt}{sh}\ {at}}a\ $ | ||
| $ \frac{s-b}{(s-b)^2-a^2} \ $ | $ e^{bt} {ch}\ {at}\ $ | ||
| $ \frac1{(s-a)(s-b)},\ a \ne b\ $ | $ \frac{e^{bt}-e^{at}}{b-a}\ $ | ||
| $ \frac{s}{(s-a)(s-b)},\ a \ne b \ $ | $ \frac{be^{bt}-ae^{at}}{b-a}\ $ | ||
| $ \frac1{(s^2+a^2)^2}\ $ | $ \frac{\sin {at}-at\cos{at}}{2a^3}\ $ | ||
| $ \frac{s}{(s^2+a^2)^2}\ $ | $ \frac{t\sin {at}}{2a}\ $ | ||
| $ \frac{s^2}{(s^2+a^2)^2}\ $ | $ \frac{\sin {at}+at\cos {at}}{2a}\ $ | ||
| $ \frac{s^3}{(s^2+a^2)^2}\ $ | $ \cos {at}-\frac12at\sin {at}\ $ | ||
| $ \frac{s^2-a^2}{(s^2+a^2)^2}\ $ | $ t\cos {at}\ $ | ||
| $ \frac{1}{(s^2-a^2)^2}\ $ | $ \frac{at\ {ch}\ {at}-{sh}\ {at}}{2a^3}\ $ | ||
| $ \frac{s}{(s^2-a^2)^2}\ $ | $ \frac{t\ {sh}\ {at}}{2a}\ $ | ||
| $ \frac{s^2}{(s^2-a^2)^2}\ $ | $ \frac{{sh}\ {at}+at\ {ch}\ {at}}{2a}\ $ | ||
| $ \frac{s^3}{(s^2-a^2)^2}\ $ | $ {ch}\ {at}+\frac12at\ {sh}\ {at} \ $ | ||
| $ \frac{s^2+a^2}{(s^2-a^2)^2}\ $ | $ t\ {ch}\ {at}\ $ | ||
| $ \frac{1}{(s^2+a^2)^3}\ $ | $ \frac{(3-a^2t^2)\sin {at}-3at\cos {at}}{8a^5}\ $ | ||
| $ \frac{s}{(s^2+a^2)^3}\ $ | $ \frac{t\sin {at}-at^2\cos {at}}{8a^3}\ $ | ||
| $ \frac{s^2}{(s^2+a^2)^3}\ $ | $ \frac{(1+a^2t^2)\sin {at}-at\cos {at}}{8a^3}\ $ | ||
| $ \frac{s^3}{(s^2+a^2)^3}\ $ | $ \frac{3t\sin {at}+at^2\cos {at}}{8a}\ $ | ||
| $ \frac{s^4}{(s^2+a^2)^3}\ $ | $ \frac{(3-a^2t^2)\sin {at}+5at\cos {at}}{8a}\ $ | ||
| $ \frac{s^5}{(s^2+a^2)^3}\ $ | $ \frac{(8-a^2t^2)\cos {at}-7at\sin {at}}{8}\ $ | ||
| $ \frac{3s^2-a^2}{(s^2+a^2)^3}\ $ | $ \frac{t^2\sin {at}}{2a}\ $ | ||
| $ \frac{s^3-3a^2s}{(s^2+a^2)^3}\ $ | $ \frac12t^2\cos {at}\ $ | ||
| $ \frac{s^4-6a^2s^2+a^4}{(s^2+a^2)^4}\ $ | $ \frac16t^3\cos {at}\ $ | ||
| $ \frac{s^3-a^2s}{(s^2+a^2)^4}\ $ | $ \frac{t^3\sin {at}}{24a}\ $ | ||
| $ \frac{1}{(s^2-a^2)^3}\ $ | $ \frac{3+a^2t^2\ {sh}\ {at}-3at\ {ch}\ {at}}{8a^5}\ $ | ||
| $ \frac{s}{(s^2-a^2)^3}\ $ | $ \frac{at^2\ {ch}\ {at}-t\ {sh}\ {at}}{8a^3}\ $ | ||
| $ \frac{s^2}{(s^2-a^2)^3}\ $ | $ \frac{at\ {ch}\ {at}+(a^2t^2-1)\ {sh}\ {at}}{8a^3}\ $ | ||
| $ \frac{s^3}{(s^2-a^2)^3}\ $ | $ \frac{3t\ {sh}\ {at}+at^2\ {ch}\ {at}}{8a}\ $ | ||
| $ \frac{s^4}{(s^2-a^2)^3}\ $ | $ \frac{(3+a^2t^2)\ {sh}\ {at}+5at\ {ch}\ {at}}{8a}\ $ | ||
| $ \frac{s^5}{(s^2-a^2)^3}\ $ | $ \frac{(8+a^2t^2)\ {ch}\ {at}+7at\ {sh}\ {at}}{8}\ $ | ||
| $ \frac{3s^2+a^2}{(s^2-a^2)^3}\ $ | $ \frac{t^2\ {sh}\ {at}}{2a}\ $ | ||
| $ \frac{s^3+3a^2s}{(s^2-a^2)^3}\ $ | $ \frac12t^2\ {ch}\ {at}\ $ | ||
| $ \frac{s^4+6a^2s^2+a^4}{(s^2-a^2)^4}\ $ | $ \frac16t^3\ {ch}\ {at}\ $ | ||
| $ \frac{s^3+a^2s}{(s^2-a^2)^4}\ $ | $ \frac{t^3\ {sh}\ {at}}{24a}\ $ | ||
| $ \frac{1}{s^3-a^3}\ $ | $ \frac{e^{at/2}}{3a^2}\ $ | ||
| please continue | place formula here | ||
| Laplace Transform Pairs | |||||
|---|---|---|---|---|---|
| notes | Signal | Laplace Transform | ROC | ||
| unit impulse/Dirac delta | $ \,\!\delta(t) $ | 1 | $ \text{All}\, s \in {\mathbb C} $ | ||
| unit step function | $ \,\! u(t) $ | $ \frac{1}{s} $ | $ \mathcal{R} \mathfrak{e} \lbrace s \rbrace > 0 $ | ||
| $ \,\! -u(-t) $ | $ \frac{1}{s} $ | $ \mathcal{R} \mathfrak{e} \lbrace s \rbrace < 0 $ | |||
| $ \frac{t^{n-1}}{(n-1)!}u(t) $ | $ \frac{1}{s^{n}} $ | $ \mathcal{R} \mathfrak{e} \lbrace s \rbrace > 0 $ | |||
| $ -\frac{t^{n-1}}{(n-1)!}u(-t) $ | $ \frac{1}{s^{n}} $ | $ \mathcal{R} \mathfrak{e} \lbrace s \rbrace < 0 $ | |||
| $ \,\!e^{-\alpha t}u(t) $ | $ \frac{1}{s+\alpha} $ | $ \mathcal{R} \mathfrak{e} \lbrace s \rbrace > -\alpha $ | |||
| $ \,\! -e^{-\alpha t}u(-t) $ | $ \frac{1}{s+\alpha} $ | $ \mathcal{R} \mathfrak{e} \lbrace s \rbrace < -\alpha $ | |||
| $ \frac{t^{n-1}}{(n-1)!}e^{-\alpha t}u(t) $ | $ \frac{1}{(s+\alpha )^{n}} $ | $ \mathcal{R} \mathfrak{e} \lbrace s \rbrace > -\alpha $ | |||
| $ -\frac{t^{n-1}}{(n-1)!}e^{-\alpha t}u(-t) $ | $ \frac{1}{(s+\alpha )^{n}} $ | $ \mathcal{R} \mathfrak{e} \lbrace s \rbrace < -\alpha $ | |||
| $ \,\!\delta (t - T) $ | $ \,\! e^{-sT} $ | $ \text{All}\,\, s\in {\mathbb C} $ | |||
| $ \,\cos( \omega_0 t)u(t) $ | $ \frac{s}{s^2+\omega_0^{2}} $ | $ \mathcal{R} \mathfrak{e} \lbrace s \rbrace > 0 $ | |||
| $ \, \sin( \omega_0 t)u(t) $ | $ \frac{\omega_0}{s^2+\omega_0^{2}} $ | $ \mathcal{R} \mathfrak{e} \lbrace s \rbrace > 0 $ | |||
| $ \,e^{-\alpha t}\cos( \omega_0 t) u(t) $ | $ \frac{s+\alpha}{(s+\alpha)^{2}+\omega_0^{2}} $ | $ \mathcal{R} \mathfrak{e} \lbrace s \rbrace > -\alpha $ | |||
| $ \, e^{-\alpha t}\sin( \omega_0 t)u(t) $ | $ \frac{\omega_0}{(s+\alpha)^{2}+\omega_0^{2}} $ | $ \mathcal{R} \mathfrak{e} \lbrace s \rbrace > -\alpha $ | |||
| $ u_n(t) = \frac{d^{n}\delta (t)}{dt^{n}} $ | $ \,\!s^{n} $ | $ All\,\, s $ | |||
| $ u_{-n}(t) = \underbrace{u(t) *\dots * u(t)}_{n\,\,times} $ | $ \frac{1}{s^{n}} $ | $ \mathcal{R} \mathfrak{e} \lbrace s \rbrace > 0 $ | |||
