Line 432: Line 432:
 
| align="right" style="padding-right: 1em;" |  
 
| align="right" style="padding-right: 1em;" |  
 
| <math> \frac{s^{-a/s}}{\sqrt{s}}\ </math>
 
| <math> \frac{s^{-a/s}}{\sqrt{s}}\ </math>
| <math> \frac{\cos {2\sqrt{at}}}{\sqrt{\pit}}\ </math>
+
| <math> \frac{\cos {2\sqrt{at}}}{\sqrt{ \pi t}}\ </math>
 +
|-
 +
| align="right" style="padding-right: 1em;" |
 +
| <math> \frac{e^{-a/s}}{s^{3/2}}\ </math>
 +
| <math> \frac{\sin {2\sqrt{at}}}{\sqrt{ \pi a}}\ </math>
 +
|-
 +
| align="right" style="padding-right: 1em;" |
 +
| <math> \frac{e^{-a/s}}{s^n+1} \quad    n>-1 \ </math>
 +
| <math> \left ( \frac{t}{a} \right )^{n/2}J_n(2\sqrt{at})\ </math>
 +
|-
 +
| align="right" style="padding-right: 1em;" |
 +
| <math> \frac{e^{-a\sqrt{s}}}{\sqrt{s}}\ </math>
 +
| <math> \frac{e^{-a^2/4t}}{\sqrt{ \pi t}}\ </math>
 +
|-
 +
| align="right" style="padding-right: 1em;" |
 +
| <math> e^{-a\sqrt{s}}\ </math>
 +
| <math> \frac{a}{2\sqrt{ \pi t^3}}e^{-a^2/4t}\ </math>
 +
|-
 +
| align="right" style="padding-right: 1em;" |
 +
| <math> \frac{1-e^{-a\sqrt{s}}}{s}\ </math>
 +
| <math> erf(a/2\sqrt{t})\ </math>
 +
|-
 +
| align="right" style="padding-right: 1em;" |
 +
| <math> \frac{e^{-a\sqrt{s}}}{s}\ </math>
 +
| <math> erfc(a/2\sqrt{t})\ </math>
 +
|-
 +
| align="right" style="padding-right: 1em;" |
 +
| <math> \frac{e^{-a\sqrt{s}}}{\sqrt{s}(\sqrt{s}+b)}\ </math>
 +
| <math> e^{b(bt+a)}erfc \left ( b\sqrt{t}+\frac{a}{2\sqrt{t}} \right )\ </math>
 
|-
 
|-
 
 
| align="right" style="padding-right: 1em;" | please continue
 
| align="right" style="padding-right: 1em;" | please continue
 
| place formula here
 
| place formula here

Revision as of 18:32, 18 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


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} \left \{ \sqrt{3} \sin {\frac{\sqrt{3}at}{2}}-\cos {\frac{\sqrt{3}at}{2}}+e^{-3at/2} \right \}\ $
$ \frac{s}{s^3+a^3}\ $ $ \frac{e^{at/2}}{3a^2} \left \{ \cos {\frac{\sqrt{3}at}{2}}+ \sqrt{3}\sin {\frac{\sqrt{3}at}{2}}-e^{-3at/2} \right \}\ $
$ \frac{s^2}{s^3+a^3}\ $ $ \frac13 \left \{ e^{-at}+ 2e^{at/2} \cos {\frac{\sqrt{3}at}{2}} \right \}\ $
$ \frac{1}{s^3-a^3}\ $ $ \frac{e^{-at/2}}{3a^2} \left \{e^{3at/2}- \cos {\frac{\sqrt{3}at}{2}}- \sqrt{3}\sin {\frac{\sqrt{3}at}{2}} \right \}\ $
$ \frac{s}{s^3-a^3}\ $ $ \frac{e^{-at/2}}{3a} \left \{ \sqrt{3}\sin {\frac{\sqrt{3}at}{2}}-\cos {\frac{\sqrt{3}at}{2}}+e^{3at/2} \right \}\ $
$ \frac{s^2}{s^3-a^3}\ $ $ \frac13 \left \{ e^{at}+ 2e^{-at/2} \cos {\frac{\sqrt{3}at}{2}} \right \}\ $
$ \frac{1}{s^4+4a^4}\ $ $ \frac1{4a^3} \left (\sin {at}\ {ch}\ {at}-\cos {at}\ {sh}\ {at} \right )\ $
$ \frac{s}{s^4+4a^4}\ $ $ \frac{\sin {at}\ {sh}\ {at}}{2a^2}\ $
$ \frac{s^2}{s^4+4a^4}\ $ $ \frac1{2a} \left (\sin {at}\ {ch}\ {at}+\cos {at}\ {sh}\ {at} \right )\ $
$ \frac{s^3}{s^4+4a^4}\ $ $ \cos {at}\ {ch}\ {at}\ $
$ \frac{1}{s^4-a^4}\ $ $ \frac1{2a^3} \left (\ {sh}\ {at}-\sin {at} \right )\ $
$ \frac{s}{s^4-a^4}\ $ $ \frac1{2a^2} \left (\ {ch}\ {at}-\cos {at} \right )\ $
$ \frac{s^2}{s^4-a^4}\ $ $ \frac1{2a} \left (\ {sh}\ {at}+\sin {at} \right )\ $
$ \frac{s^3}{s^4-a^4}\ $ $ \frac12 \left (\ {ch}\ {at}+\cos {at} \right )\ $
$ \frac1{\sqrt{s+a}+\sqrt{s+b}}\ $ $ \frac{e^{-bt}-e^{-at}}{2(b-a)\sqrt{\pi t^3}}\ $
$ \frac1{s\sqrt{s+a}}\ $ $ \frac{erf\ \sqrt{at}}{\sqrt{a}}\ $
$ \frac1{\sqrt{s}(s-a)}\ $ $ \frac{e^{at}\ {erf}\ \sqrt{at}}{\sqrt{a}}\ $
$ \frac1{\sqrt{s-a}+b}\ $ $ e^{at} \left \{\frac1{\sqrt{\pi t}}-be^{b^{2}t}\ {erfc}\ (b\sqrt{t}) \right \}\ $
$ \frac1{\sqrt{s^2+a^2}}\ $ $ J_0(at)\ $
$ \frac1{\sqrt{s^2-a^2}}\ $ $ I_0(at)\ $
$ \frac{{\left (\sqrt{s^2+a^2}-s \right )}^n}{\sqrt{s^2+a^2}},\quad n>-1 \ $ $ a^nJ_n(at)\ $
$ \frac{{\left (s- \sqrt{s^2-a^2} \right )}^n}{\sqrt{s^2-a^2}},\quad n>-1 \ $ $ a^nI_n(at)\ $
$ \frac{e^{b \left (s- \sqrt{s^2+a^2} \right )}}{\sqrt{s^2+a^2}} \ $ $ J_0(a\sqrt{t(t+2b)})\ $
$ \frac{e^{-b\sqrt{s^2+a^2}}}{\sqrt{s^2+a^2}} \ $ $ \begin{cases} J_0(a\sqrt{t^2-b^2}) & t>b \\ 0 &t<b \end{cases} \ $
$ \frac1{(s^2+a^2)^{3/2}}\ $ $ tJ_0(at)\ $
$ \frac{s^2}{(s^2+a^2)^{3/2}}\ $ $ J_0(at)-atJ_1(at)\ $
$ \frac1{(s^2-a^2)^{3/2}}\ $ $ \frac{tI_1(at)}{a}\ $
$ \frac{s}{(s^2+a^2)^{3/2}}\ $ $ I_0(at)+atI_1(at)\ $
$ \frac1{s(e^s-1)}\ =\ \frac{e^{-s}}{s(1-e^{-s})}\ $ $ f(t)=n,\ n \leqq t\ <n+1,\ n=0,1,2,... \ $
$ \frac1{s(e^s-r)}\ =\ \frac{e^{-s}}{s(1-re^{-s})}\ $ $ f(t)= \sum_{k=1}^{[t]} r^k\ $
$ \frac{s^s-1}{s(e^s-r)}\ =\ \frac{1-e^{-s}}{s(1-re^{-s})}\ $ $ f(t)= r^n,\ n\leqq t<n+1,\ n=0,1,2,...\ $
$ \frac{s^{-a/s}}{\sqrt{s}}\ $ $ \frac{\cos {2\sqrt{at}}}{\sqrt{ \pi t}}\ $
$ \frac{e^{-a/s}}{s^{3/2}}\ $ $ \frac{\sin {2\sqrt{at}}}{\sqrt{ \pi a}}\ $
$ \frac{e^{-a/s}}{s^n+1} \quad n>-1 \ $ $ \left ( \frac{t}{a} \right )^{n/2}J_n(2\sqrt{at})\ $
$ \frac{e^{-a\sqrt{s}}}{\sqrt{s}}\ $ $ \frac{e^{-a^2/4t}}{\sqrt{ \pi t}}\ $
$ e^{-a\sqrt{s}}\ $ $ \frac{a}{2\sqrt{ \pi t^3}}e^{-a^2/4t}\ $
$ \frac{1-e^{-a\sqrt{s}}}{s}\ $ $ erf(a/2\sqrt{t})\ $
$ \frac{e^{-a\sqrt{s}}}{s}\ $ $ erfc(a/2\sqrt{t})\ $
$ \frac{e^{-a\sqrt{s}}}{\sqrt{s}(\sqrt{s}+b)}\ $ $ e^{b(bt+a)}erfc \left ( b\sqrt{t}+\frac{a}{2\sqrt{t}} \right )\ $
please continue place formula here
please continue place formula here
please continue place formula here
please continue place formula here
please continue place formula here
please continue place formula here
please continue place formula here
please continue place formula here
please continue place formula here
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 $

Back to Collective Table

Alumni Liaison

Basic linear algebra uncovers and clarifies very important geometry and algebra.

Dr. Paul Garrett