matlab assignment

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lab_week_6.zip

Laplace_Table(4).pdf

Table of Laplace Transforms ( ) ( ){ }1f t F s−= L ( ) ( ){ }F s f t= L ( ) ( ){ }1f t F s−= L ( ) ( ){ }F s f t= L 1. 1

1 s

2. a te 1

s a−

3. , 1, 2, 3,nt n = … 1 !

n n

s + 4. pt , p > -1

( ) 1

1 p

p s +

Γ +

5. t 3 22s

π 6.

1 2 , 1, 2, 3,nt n− = …

( ) 1 2

1 3 5 2 1 2 nn

n s

π +

⋅ ⋅ −L

7. ( )sin at 2 2 a

s a+ 8. ( )cos at 2 2

s s a+

9. ( )sint at ( )22 2 2as

s a+ 10. ( )cost at ( )

2 2

22 2

s a

s a

+

11. ( ) ( )sin cosat at at− ( ) 3

22 2

2a

s a+ 12. ( ) ( )sin cosat at at+ ( )

2

22 2

2as

s a+

13. ( ) ( )cos sinat at at− ( )

( )

2 2

22 2

s s a

s a

+ 14. ( ) ( )cos sinat at at+

( ) ( )

2 2

22 2

3s s a

s a

+

+

15. ( )sin at b+ ( ) ( ) 2 2

sin coss b a b s a

+ +

16. ( )cos at b+ ( ) ( )2 2 cos sins b a b

s a − +

17. ( )sinh at 2 2 a

s a− 18. ( )cosh at 2 2

s s a−

19. ( )sinat bte ( )2 2 b

s a b− + 20. ( )cosat bte ( )2 2

s a s a b

− +

21. ( )sinhat bte ( )2 2 b

s a b− − 22. ( )coshat bte ( )2 2

s a s a b

− −

23. , 1, 2, 3,n att n =e … ( ) 1 !

n n

s a +

− 24. ( )f ct 1 sF

c c      

25. ( ) ( )cu t u t c= − Heaviside Function

cs

s

−e 26. ( )t cδ −

Dirac Delta Function cs−e

27. ( ) ( )cu t f t c− ( )cs F s−e 28. ( ) ( )cu t g t ( ){ }cs g t c− +e L 29. ( )ct f te ( )F s c− 30. ( ) , 1, 2, 3,nt f t n = … ( ) ( ) ( )1 n nF s−

31. ( )1 f t t

( ) s

F u du ∞

∫ 32. ( )0 t

f v dv∫ ( )F s s

33. ( ) ( ) 0

t f t g dτ τ τ−∫ ( ) ( )F s G s 34. ( ) ( )f t T f t+ =

( ) 0

1

T st

sT

f t dt−

−− ∫ e

e

35. ( )f t′ ( ) ( )0sF s f− 36. ( )f t′′ ( ) ( ) ( )2 0 0s F s sf f ′− − 37. ( ) ( )nf t ( ) ( ) ( ) ( ) ( ) ( ) ( )2 11 20 0 0 0n nn n ns F s s f s f sf f− −− − ′− − − −L

Table Notes 1. This list is not a complete listing of Laplace transforms and only contains some of

the more commonly used Laplace transforms and formulas.

2. Recall the definition of hyperbolic functions.

( ) ( )cosh sinh 2 2

t t t t

t t − −+ −

= = e e e e

3. Be careful when using “normal” trig function vs. hyperbolic functions. The only

difference in the formulas is the “+ a2” for the “normal” trig functions becomes a “- a2” for the hyperbolic functions!

4. Formula #4 uses the Gamma function which is defined as ( ) 1

0

x tt x dx ∞ − −Γ = ∫ e

If n is a positive integer then, ( )1 !n nΓ + =

The Gamma function is an extension of the normal factorial function. Here are a couple of quick facts for the Gamma function

( ) ( )

( ) ( ) ( ) ( ) ( )

1

1 2 1

1 2

p p p

p n p p p p n

p

π

Γ + = Γ

Γ + + + + − =

Γ

  Γ = 

 

L

Laplace_workshop_Week6(1).pdf

1

Name__________________________________________________Section________________________

Part 1: Given the following expressions for Y(s) find y(t)

1.1 𝑌(𝑠) = 𝑠−18

(𝑠+2)(𝑠−3)

1.2 𝑌(𝑠) = −3𝑠2−14𝑠+32

(𝑠+4)(𝑠2+4) =

𝐴

𝑠+4 +

𝐵𝑠+𝐶

𝑠2+4

1.3 𝑌(𝑠) = 2𝑠−3

𝑠2+2𝑠+10 hint complete square

2

1.4 𝑌(𝑠) = 90

(𝑠+5)(𝑠+2)2 repeated roots

Part 2: For the following problems solve the IVP - be careful of initial conditions and coefficients which

change in each problem

1.5 𝑦′′ + 6𝑦′ + 8𝑦 = 0 y’(0) = -4, y(0) = 1

1.6 𝑦′′ + 6𝑦′ + 8𝑦 = 0 y’(0) = 1, y(0) = 1

1.7 𝑦′′ + 6𝑦′ + 8𝑦 = 5 y’(0) = 1, y(0) = 1

3

1.8 𝑦′′ + 5𝑦′ + 6𝑦 = 5𝑒−5𝑡 y’(0) = 0, y(0) = 0

1.9 𝑦′ + 6𝑦 = t y(0) = 1