Somewhat Easy Differential Equation Question

In summary, the minimum number of nonhomogeneous equations that must be solved using the Method of Undetermined Coefficients and the Principle of Superposition to find a particular solution for the given equation is 3. This is because each unique term on the right side must be solved separately and then summed together to find the general solution. The et terms can be grouped and solved together, and the sin4t and cos4t terms can also be grouped. The equation cos^2(t) + sin^2(t) = 1 must be used.
  • #1
bosox09
7
0
This is a straightforward concept-type question that I already know the answer to, but I need someone to shed some light on HOW this is figured out. I have an idea but this is probably going to be asked of me on my final exam and I want to know the method behind this problem.

Homework Statement



Given the equation 5y''(t)−y'(t)+7y(t) = 3te4tcos2t + t2et + 4t3e2tsin4t − (2/3)et + 9e2tcos4t, if the Method of Undetermined Coefficients and the Principle of Superposition are used to find a particular solution, what is the minimum number of nonhomogeneous equations which must be solved?

Homework Equations



The answer is 3. I believe this is because each individual, unique term on the right side has to be solved separately, and then each of these solutions are summed to find the general solution to the diff eq. Even though there are 5 separate terms on the right side, the et terms can be grouped and solved at once, and since cost + sint = 1, I'm guessing the sin4t and cos4t terms can be grouped as well. Am I way off?

Thanks for the help, hopefully this is a quickie.
 
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  • #2
Don't you mean [tex] cos^2(t) + sin^2(t) = 1 [/tex]?
 
  • #3
Hahahahahaha ugh...duh! Alright then can anyone explain why it's only 3 instead of 4?
 

Related to Somewhat Easy Differential Equation Question

What is a differential equation?

A differential equation is a mathematical equation that describes the relationship between a function and its derivatives. It is commonly used to model dynamic systems in physics, engineering, and other scientific fields.

What makes a differential equation "somewhat easy"?

A "somewhat easy" differential equation is one that can be solved using basic techniques and does not require advanced mathematical knowledge. It typically involves simple functions, such as polynomials or exponential functions, and has a straightforward structure.

What are the different types of differential equations?

There are several types of differential equations, including ordinary differential equations (ODEs), partial differential equations (PDEs), and stochastic differential equations (SDEs). ODEs involve a single independent variable, while PDEs involve multiple variables. SDEs also include a random component.

How do you solve a differential equation?

The method for solving a differential equation depends on its type and complexity. Some common techniques include separation of variables, integrating factors, and using substitution or series solutions. It is important to first identify the type of differential equation and then choose an appropriate method for solving it.

What are some real-world applications of differential equations?

Differential equations have numerous applications in fields such as physics, engineering, economics, and biology. They are used to model systems such as population growth, chemical reactions, and electrical circuits. They are also essential in the study of dynamics and control systems.

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