2nd order inhomogenous equations

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In summary, the conversation discusses finding the general solution to a differential equation and determining the particular integral for a given function. The conversation also mentions using latex tags and provides equations for the general and particular solutions.
  • #1
adichy
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Homework Statement



Find the general solution to the differential equation
[tex]\frac{d^2y}{dx^2}[/tex] -2*[tex]\frac{dy}{dx}[/tex] +2y =g(x)

where g(x) = −14 cos(2x) − 2 sin(2x)

Homework Equations





The Attempt at a Solution


ive found the homogenous solution which is
y=e^x (ae^ix +be^-ix)

what I am not sure of is for the particular intergral do i do
Csin(2x)+Dcos(2x)+Esin(2x)+Fcos(2x)
or is it just Csin(2x)+Dcos(2x)
please advise

thanks

edit:cant seem to get the latex to come out right basically its d^2y/dx^2 - 2(dy/dx) + 2y=0
 
Last edited:
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  • #2
Tip: Use only one pair of tex tags, one at the beginning of the equation and one at the end.
adichy said:

Homework Statement



Find the general solution to the differential equation
[tex]\frac{d^2y}{dx^2}[/tex] -2*[tex]\frac{dy}{dx}[/tex] +2y =g(x)

where g(x) = −14 cos(2x) − 2 sin(2x)

Homework Equations





The Attempt at a Solution


ive found the homogenous solution which is
y=e^x (ae^ix +be^-ix)
You can also write this as y = ex(A cos(x) + B sin(x))
adichy said:
what I am not sure of is for the particular intergral do i do
Csin(2x)+Dcos(2x)+Esin(2x)+Fcos(2x)
or is it just Csin(2x)+Dcos(2x)
For your particular solution, use yp = Csin(2x)+Dcos(2x)
adichy said:
please advise

thanks

edit:cant seem to get the latex to come out right basically its d^2y/dx^2 - 2(dy/dx) + 2y=0
 
  • #3
I would start with a particular solution of:
[tex]
P.I.=A\cos 2x+B\sin 2x
[/tex]
and the general solution is:
[tex]
y=Ce^{\lambda_{1}x}+De^{\lambda_{2}x}
[/tex]
where the lambda are solutions of:
[tex]
\lambda^{2}-2\lambda+2=0
[/tex]
 

Related to 2nd order inhomogenous equations

1. What is a 2nd order inhomogeneous equation?

A 2nd order inhomogeneous equation is a type of differential equation that involves a second derivative of a function, and also has a non-zero term on the right-hand side of the equation.

2. How is a 2nd order inhomogeneous equation solved?

To solve a 2nd order inhomogeneous equation, the complementary function and particular integral must be found. The complementary function represents the solution to the corresponding homogeneous equation, while the particular integral represents a specific solution to the inhomogeneous equation. The sum of these two solutions gives the general solution to the equation.

3. What is the difference between a 2nd order inhomogeneous equation and a 2nd order homogeneous equation?

A 2nd order homogeneous equation has a zero term on the right-hand side, while a 2nd order inhomogeneous equation has a non-zero term on the right-hand side. This means that the solutions to the two types of equations are different. The general solution to a 2nd order homogeneous equation will only have two arbitrary constants, while the general solution to a 2nd order inhomogeneous equation will have an additional particular integral term.

4. Can a 2nd order inhomogeneous equation have multiple solutions?

Yes, a 2nd order inhomogeneous equation can have multiple solutions. The general solution to the equation will have two arbitrary constants, so there are infinite possible solutions. Additionally, the particular integral term can also have multiple solutions depending on the form of the non-zero term on the right-hand side of the equation.

5. What are some real-world applications of 2nd order inhomogeneous equations?

2nd order inhomogeneous equations can be used to model a variety of physical phenomena, such as the motion of a damped harmonic oscillator or the growth of a population in the presence of a limiting factor. They are also commonly used in engineering fields to analyze and design systems with complex dynamics, such as electrical circuits or mechanical systems.

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