Help undetermined coefficients

In summary, the conversation is about solving the equation y"+y'+4y = 2sinh(T), with the given hint that sinh t = (e^t - e^-t)/2. The person mentions their guess of aE^t +Be^-t=Y, but is unsure if it is correct. They are advised to try putting it into the equation and also suggested to use y= C cosh(t)+ D sinh(t) if they are familiar with hyperbolic functions. They mention trying this guess but getting the wrong answer and plan to seek help in the "Homework" forum.
  • #1
SoulofLoneWlf
29
0
i solved homogenous but
y"+y'+4y = 2sinh(T)
is giving me trouble
also have a hint
sinh t = (e^t - e^-t)/2

also my "guess" was
aE^t +Be^-t=Y
maybe my guess was wrong?
 
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  • #2
That should be fine.
 
  • #3
Why are you asking? Have you tried putting that into the equation? If you are used to working with hyperbolic functions directly, you can also use y= C cosh(t)+ D sinh(t).
 
  • #4
tried this guess but yield wrong answer guess ill do a few more times thanks all
 
  • #5
In the "Homework" forum, you can put in your work with wrong answer, and ask where you went wrong.
 

1. What is the method of undetermined coefficients?

The method of undetermined coefficients is a technique used to find the particular solution of a non-homogeneous linear differential equation. It involves guessing the form of the particular solution and determining the coefficients by substitution into the original equation.

2. When is the method of undetermined coefficients applicable?

The method of undetermined coefficients is applicable to solving non-homogeneous linear differential equations with constant coefficients. It is not applicable to non-linear differential equations or those with variable coefficients.

3. How do you determine the form of the particular solution in the method of undetermined coefficients?

The form of the particular solution is determined by the type of non-homogeneous term in the equation. For example, if the non-homogeneous term is a polynomial of degree n, the particular solution will be a polynomial of degree n with undetermined coefficients.

4. Can the method of undetermined coefficients be used for all types of non-homogeneous terms?

No, the method of undetermined coefficients can only be used for certain types of non-homogeneous terms such as polynomials, exponential functions, sine and cosine functions, and combinations of these. For other types of non-homogeneous terms, other methods such as variation of parameters may be used.

5. What is the difference between the complementary and particular solutions in the method of undetermined coefficients?

The complementary solution is the general solution to the associated homogeneous equation, while the particular solution is a specific solution that satisfies the non-homogeneous equation. The general solution to the non-homogeneous equation is the sum of the complementary and particular solutions.

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