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logo1 Underlying Theorem Example (Equation) Example (System) Translating Higher Order Equations/Systems to First Order Systems Bernd Schr ¨ oder Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Translating Higher Order Equations/Systems to First Order Systems

Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

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Page 1: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translating Higher OrderEquations/Systems to First Order Systems

Bernd Schroder

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 2: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Intermediate Derivatives Become DummyVariables

Let a0(t), . . . ,an−1(t) and g(t) be differentiable functions. Thefunction y is a solution of the nth order linear differentialequation y(n) +an−1(t)y(n−1) + · · ·+a1(t)y′ +a0(t)y = g(t) ifand only if y0 := y, y1 := y′, . . . , yn−1 := y(n−1) is a solution ofthe system of linear equations

y′0 = y1

y′1 = y2...

...y′n−2 = yn−1

y′n−1 = −an−1(t)yn−1 −·· ·−a1(t)y1 −a0(t)y0 +g(t).

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 3: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Intermediate Derivatives Become DummyVariables

Let a0(t), . . . ,an−1(t) and g(t) be differentiable functions. Thefunction y is a solution of the nth order linear differentialequation y(n) +an−1(t)y(n−1) + · · ·+a1(t)y′ +a0(t)y = g(t) ifand only if y0 := y, y1 := y′, . . . , yn−1 := y(n−1) is a solution ofthe system of linear equations

y′0 = y1

y′1 = y2...

...y′n−2 = yn−1

y′n−1 = −an−1(t)yn−1 −·· ·−a1(t)y1 −a0(t)y0 +g(t).

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 4: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′ +4y′ +5y = 0, y(0) = 0, y′(0) = 1 Into an IVPfor a First Order System

Idea: y0 = y, y1 = y′

y1 = y′0y′1 +4y1 +5y0 = 0

y0(0) = 0y1(0) = 1

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 5: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′ +4y′ +5y = 0, y(0) = 0, y′(0) = 1 Into an IVPfor a First Order System

Idea: y0 = y, y1 = y′

y1 = y′0y′1 +4y1 +5y0 = 0

y0(0) = 0y1(0) = 1

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 6: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′ +4y′ +5y = 0, y(0) = 0, y′(0) = 1 Into an IVPfor a First Order System

Idea: y0 = y, y1 = y′

y1 = y′0

y′1 +4y1 +5y0 = 0y0(0) = 0y1(0) = 1

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 7: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′ +4y′ +5y = 0, y(0) = 0, y′(0) = 1 Into an IVPfor a First Order System

Idea: y0 = y, y1 = y′

y1 = y′0y′1

+4y1 +5y0 = 0y0(0) = 0y1(0) = 1

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 8: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′ +4y′ +5y = 0, y(0) = 0, y′(0) = 1 Into an IVPfor a First Order System

Idea: y0 = y, y1 = y′

y1 = y′0y′1 +4y1

+5y0 = 0y0(0) = 0y1(0) = 1

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 9: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′ +4y′ +5y = 0, y(0) = 0, y′(0) = 1 Into an IVPfor a First Order System

Idea: y0 = y, y1 = y′

y1 = y′0y′1 +4y1 +5y0

= 0y0(0) = 0y1(0) = 1

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 10: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′ +4y′ +5y = 0, y(0) = 0, y′(0) = 1 Into an IVPfor a First Order System

Idea: y0 = y, y1 = y′

y1 = y′0y′1 +4y1 +5y0 = 0

y0(0) = 0y1(0) = 1

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 11: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′ +4y′ +5y = 0, y(0) = 0, y′(0) = 1 Into an IVPfor a First Order System

Idea: y0 = y, y1 = y′

y1 = y′0y′1 +4y1 +5y0 = 0

y0(0) = 0

y1(0) = 1

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 12: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′ +4y′ +5y = 0, y(0) = 0, y′(0) = 1 Into an IVPfor a First Order System

Idea: y0 = y, y1 = y′

y1 = y′0y′1 +4y1 +5y0 = 0

y0(0) = 0y1(0) = 1

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 13: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′ +4y′ +5y = 0, y(0) = 0, y′(0) = 1 Into an IVPfor a First Order System

y′0 = y1

y′1 = −4y1 −5y0

y0(0) = 0y1(0) = 1

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 14: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′ +4y′ +5y = 0, y(0) = 0, y′(0) = 1 Into an IVPfor a First Order System

y′0 = y1

y′1 = −4y1 −5y0

y0(0) = 0y1(0) = 1

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 15: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′ +4y′ +5y = 0, y(0) = 0, y′(0) = 1 Into an IVPfor a First Order System

y′0 = y1

y′1 = −4y1 −5y0

y0(0) = 0y1(0) = 1

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 16: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′ +4y′ +5y = 0, y(0) = 0, y′(0) = 1 Into an IVPfor a First Order System

y′0 = y1

y′1 = −4y1 −5y0

y0(0) = 0

y1(0) = 1

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 17: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′ +4y′ +5y = 0, y(0) = 0, y′(0) = 1 Into an IVPfor a First Order System

y′0 = y1

y′1 = −4y1 −5y0

y0(0) = 0y1(0) = 1

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 18: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2 −u1 +2u4 = 0

u4 = u′3

u′4 −2u3 +u2 −2u1 = 0

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 19: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2

u2 = u′1

u′2 +3u2 −u1 +2u4 = 0

u4 = u′3

u′4 −2u3 +u2 −2u1 = 0

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 20: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2 −u1 +2u4 = 0

u4 = u′3

u′4 −2u3 +u2 −2u1 = 0

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 21: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2

+3u2 −u1 +2u4 = 0u4 = u′

3

u′4 −2u3 +u2 −2u1 = 0

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 22: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2

−u1 +2u4 = 0u4 = u′

3

u′4 −2u3 +u2 −2u1 = 0

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 23: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2 −u1

+2u4 = 0u4 = u′

3

u′4 −2u3 +u2 −2u1 = 0

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 24: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2 −u1 +2u4

= 0u4 = u′

3

u′4 −2u3 +u2 −2u1 = 0

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 25: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2 −u1 +2u4 = 0

u4 = u′3

u′4 −2u3 +u2 −2u1 = 0

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 26: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2 −u1 +2u4 = 0

u4 = u′3

u′4 −2u3 +u2 −2u1 = 0

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 27: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2 −u1 +2u4 = 0

u4 = u′3

u′4

−2u3 +u2 −2u1 = 0u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 28: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2 −u1 +2u4 = 0

u4 = u′3

u′4 −2u3

+u2 −2u1 = 0u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 29: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2 −u1 +2u4 = 0

u4 = u′3

u′4 −2u3 +u2

−2u1 = 0u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 30: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2 −u1 +2u4 = 0

u4 = u′3

u′4 −2u3 +u2 −2u1

= 0u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 31: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2 −u1 +2u4 = 0

u4 = u′3

u′4 −2u3 +u2 −2u1 = 0

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 32: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2 −u1 +2u4 = 0

u4 = u′3

u′4 −2u3 +u2 −2u1 = 0

u1(0) = 0

u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 33: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2 −u1 +2u4 = 0

u4 = u′3

u′4 −2u3 +u2 −2u1 = 0

u1(0) = 0 u2(0) = 1

u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 34: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

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Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2 −u1 +2u4 = 0

u4 = u′3

u′4 −2u3 +u2 −2u1 = 0

u1(0) = 0 u2(0) = 1u3(0) = 2

u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 35: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

Idea: u1 := y1, u2 := y′1, u3 := y2, u4 := y′2u2 = u′

1

u′2 +3u2 −u1 +2u4 = 0

u4 = u′3

u′4 −2u3 +u2 −2u1 = 0

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 36: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

u′1 = u2

u′2 = −3u2 +u1 −2u4

u′3 = u4

u′4 = 2u3 −u2 +2u1

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 37: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

u′1 = u2

u′2 = −3u2 +u1 −2u4

u′3 = u4

u′4 = 2u3 −u2 +2u1

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 38: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

u′1 = u2

u′2 = −3u2 +u1 −2u4

u′3 = u4

u′4 = 2u3 −u2 +2u1

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 39: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

u′1 = u2

u′2 = −3u2 +u1 −2u4

u′3 = u4

u′4 = 2u3 −u2 +2u1

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 40: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

u′1 = u2

u′2 = −3u2 +u1 −2u4

u′3 = u4

u′4 = 2u3 −u2 +2u1

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 41: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

u′1 = u2

u′2 = −3u2 +u1 −2u4

u′3 = u4

u′4 = 2u3 −u2 +2u1

u1(0) = 0

u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 42: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

u′1 = u2

u′2 = −3u2 +u1 −2u4

u′3 = u4

u′4 = 2u3 −u2 +2u1

u1(0) = 0 u2(0) = 1

u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 43: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

u′1 = u2

u′2 = −3u2 +u1 −2u4

u′3 = u4

u′4 = 2u3 −u2 +2u1

u1(0) = 0 u2(0) = 1u3(0) = 2

u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems

Page 44: Translating Higher Order Equations/Systems to First Order Systems · 2008. 11. 6. · Translating Higher Order Equations/Systems to First Order Systems. logo1 Underlying Theorem Example

logo1

Underlying Theorem Example (Equation) Example (System)

Translate the Initial Value Problemy′′1 +3y′1 − y1 +2y′2 = 0, y′′2 −2y2 + y′1 −2y1 = 0,y1(0) = 0, y′1(0) = 1, y2(0) = 2, y′2(0) = 3 Into anIVP for a First Order System

u′1 = u2

u′2 = −3u2 +u1 −2u4

u′3 = u4

u′4 = 2u3 −u2 +2u1

u1(0) = 0 u2(0) = 1u3(0) = 2 u4(0) = 3

Bernd Schroder Louisiana Tech University, College of Engineering and Science

Translating Higher Order Equations/Systems to First Order Systems