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Table of Laplace Transforms
f ( t ) = L -^1 { F ( s )} F ( s ) = L { f ( t )} f ( t ) = L -^1 { F ( s )} F ( s ) = L{ f ( t )}
s
- (^) e at
s - a
- t n , n = 1, 2,3,K (^1)
n
n s +^
- (^) t p , p > -
1
p
p s +
G +
- (^) t (^) 3 2 s^2
p
(^12) t n^ -^ , n = 1, 2,3,K
(^12)
2 n n
n s
p
◊ ◊ L -
7. sin^ ( at^ ) 2 2
a s + a
8. cos^ ( at^ ) 2 2
s s + a
9. t^ sin( at^ )
2 2 2
2 as s + a
10. t^ cos( at^ )
2 2 2 2 2
s a s a
11. sin^ ( at^ ) -^ at^ cos( at )
3 2 2 2
2 a s + a
12. sin^ ( at^ ) +^ at^ cos( at )
2 2 2 2
2 as s + a
13. cos ( at ) - at sin( at )
2 2
2 2 2
s s a
s a
14. cos ( at ) + at sin( at )
2 2
2 2 2
s s 3 a
s a
15. sin ( at + b )
2 2
s sin b a cos b s a
16. cos ( at + b )
2 2
s cos b a sin b s a
17. sinh ( at ) 2 2
a s - a
18. cosh ( at ) 2 2
s s - a
19. e at^ sin( bt )
(^2 )
b s - a + b
20. e at^ cos( bt )
(^2 )
s a s a b
21. e at^^ sinh( bt )
(^2 )
b s - a - b
22. e at^^ cosh( bt )
(^2 )
s a s a b
- t n^ e at , n =1, 2,3,K
1
n
n s a
24. f ( ct )
1 s F c c
Ê ˆ
Á ˜
Ë ¯
25. uc^ (^ t^ )^ =^ u t (^^ - c )
Heaviside Function
cs
s
e^ -
26.^ d^ (^ t^ - c )
Dirac Delta Function
e -^ cs
27. uc^ ( t^ ) f^ ( t^ -^ c )^ e^ - cs^ F^ ( s ) 28. uc^ ( t^ ) g t (^ ) e -^^ cs^ L{ g t (^ + c )}
29. e ct^^ f^ ( t ) F^ ( s^ -^ c ) 30.^ t^ nf^ ( t^ ) ,^ n^ =^ 1, 2,3,K^ ( 1 ) (^ )^ ( )
n (^) n
f t t
s F u du (^ )
Ú 32.^0 (^ )
t
Ú^ f^ v dv (^ )
F s s
t
Ú^ f^ t^ -^ t^ g^ t^ dt F^ (^ s G s )^ (^^ ) 34.^ f^ (^ t^ +^ T^ )^ =^ f^ (^ t )^0 ( )
T (^) st
sT
Ú e
e
35. f^ ¢^ ( t ) sF^ ( s^ ) -^ f ( 0 ) 36. f^ ¢¢^ ( t ) s F^2^ ( s^ ) -^ sf^ ( 0 )^ - f^ ¢( 0 )
37. f (^ n )^ ( t ) s Fn^ ( s ) - s n^ -^1 f ( 0 ) - s n -^2 f ¢( 0 ) L- sf (^ n^ -^2 )^ ( 0 ) - f (^ n -^1 )^ ( 0 )
Table Notes
- This list is not a complete listing of Laplace transforms and only contains some of the more commonly used Laplace transforms and formulas.
- Recall the definition of hyperbolic functions.
cosh ( ) sinh( )
t t t t t t
+ -^ - -
e e e e
- Be careful when using “normal” trig function vs. hyperbolic functions. The only difference in the formulas is the “+ a^2 ” for the “normal” trig functions becomes a “- a^2 ” for the hyperbolic functions!
- Formula #4 uses the Gamma function which is defined as
( )^ t^ 0^ x^ xt^^1 dx
If n is a positive integer then,
G ( n + 1 ) = n!
The Gamma function is an extension of the normal factorial function. Here are a couple of quick facts for the Gamma function
p p p p n p p p p n p
p
G + = G
G +
G
Ê ˆ
G Á ˜=
Ë ¯
L