Second order DE quick question

The two solutions can be combined to form the general solution.In summary, the A and B in the general solution for y = e^(mx) represent the 'freedom' of the ODE and are granted by its linear character. The A represents the first independent solution and B represents the second independent solution, which can be combined to form the general solution.
  • #1
converting1
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I don't understand where the A and B come from,

if y = e^(mx), would the general solutions be y = Ae^(mx) + Be^(m_1x) assuming there are two distinct roots of the auxiliary equation? If anyone could clear this up, thanks.
 
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  • #2
A and B are the 'freedom' of the ODE, that is the maximum number of arbitrary constants which multiply the linear independent solutions. This 'freedom' is granted by the linear character of the equation (which comes from the linear characted of the differentiation operator).

In other words, if e^(alpha x) is a solution of the ODE, so is any A times e^(alpha x). The B comes from the second independent solution.
 

FAQ: Second order DE quick question

What is a second order differential equation?

A second order differential equation is a type of mathematical equation that involves the second derivative of a variable with respect to another variable. It is commonly used in physics, engineering, and other fields to model systems that involve acceleration, such as the motion of objects or changes in electrical currents.

How is a second order differential equation solved?

There are several methods for solving a second order differential equation, including separation of variables, substitution, and the method of undetermined coefficients. The specific method used depends on the type of equation and any initial or boundary conditions that are given.

What is the difference between a linear and a nonlinear second order differential equation?

A linear second order differential equation is one where the dependent variable and its derivatives appear to the first power, while a nonlinear equation has terms that involve powers other than one. Linear equations are typically easier to solve and have well-defined solutions, while nonlinear equations can have more complex and unpredictable behavior.

Can second order differential equations be applied to real-world problems?

Yes, second order differential equations are used to model a wide range of physical and natural phenomena, such as the motion of objects under the influence of forces, the growth and decay of populations, and the spread of diseases. They are also commonly used in engineering to analyze and design systems and processes.

What are the applications of second order differential equations in science and engineering?

Second order differential equations have many practical applications in science and engineering, including modeling the behavior of mechanical systems, analyzing electrical circuits, predicting the trajectory of projectiles, and understanding the dynamics of chemical reactions. They are also used in the fields of economics, biology, and ecology to study complex systems and make predictions about their behavior.

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