Higher-Order Differential Equations

In summary, the general solution for the given higher-order differential equation is x(t) = c1e2t + c2em2t + c3em3t, where m2 and m3 are found using the quadratic formula with the auxiliary equation m3 - m2 - 4 = 0. The other two solutions are of the form a +/- b.
  • #1
recon_ind
8
0

Homework Statement



Find the general solution of the given higher-order differential equation.

d3x/(dt3) - d2x/(dt2) - 4x = 0

Homework Equations



Use an auxiliary equation such as m3 - m2 - 4 = 0

The Attempt at a Solution



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  • #2
That is the auxiliary equation you want to use. As it turns out, the left side can be factored, yielding (m - 2)(m2 + m + 2) = 0

There are three distinct solutions, so the solution to this homogeneous problem will be x(t) = c1e2t + c2em2t + c3em3t. All you have to do is find the other two constants, m2 and m3.
 
  • #3
So, I should just use the quadratic formula to find the other two solutions?

Thanks man.
 
  • #4
The other two solutions are of the form [tex]\alpha[/tex] [tex]\pm[/tex] [tex]\beta[/tex]
 
  • #5
recon_ind said:
So, I should just use the quadratic formula to find the other two solutions?
Yes. And yes, the two solutions are of the form a +/- b. One of your values of m will be a + b, and the other will be a - b.
 

What is a higher-order differential equation?

A higher-order differential equation is an equation that involves derivatives of a function up to a certain order. For example, a second-order differential equation would involve the second derivative of a function.

Why are higher-order differential equations important?

Higher-order differential equations are important because they are used to model many physical phenomena, such as motion, heat transfer, and electrical circuits. They also have practical applications in engineering, physics, and other sciences.

What are the different types of higher-order differential equations?

There are several types of higher-order differential equations, including linear and nonlinear equations, homogeneous and nonhomogeneous equations, and constant coefficient and variable coefficient equations. Each type has its own unique properties and methods for solving.

How do you solve a higher-order differential equation?

The general method for solving a higher-order differential equation involves finding a function that satisfies the equation. This can be done by using various techniques such as separation of variables, substitution, or using specific formulas for certain types of equations.

What are the boundary conditions for a higher-order differential equation?

The boundary conditions for a higher-order differential equation are the initial values or values at certain points that are used to determine the specific solution to the equation. These conditions are necessary to uniquely determine the solution to the equation.

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