(d2+4)y=sin3x

3 min read Jul 03, 2024
(d2+4)y=sin3x

Solving the Equation (d2+4)y = sin(3x)

In this article, we will discuss how to solve the differential equation (d2+4)y = sin(3x). This equation is a second-order linear ordinary differential equation, and we will use the method of undetermined coefficients to find the general solution.

Step 1: Find the Homogeneous Solution

The homogeneous equation is obtained by setting the right-hand side of the equation equal to zero:

(d2+4)y = 0

This is a second-order linear homogeneous differential equation with constant coefficients. The characteristic equation is:

r^2 + 4 = 0

Solving for r, we get:

r = ±2i

The general solution to the homogeneous equation is:

y_h = c1 cos(2x) + c2 sin(2x)

Step 2: Find a Particular Solution

To find a particular solution, we will use the method of undetermined coefficients. We will assume that the particular solution has the form:

y_p = A sin(3x) + B cos(3x)

Substituting this into the original equation, we get:

(d2+4)(A sin(3x) + B cos(3x)) = sin(3x)

Expanding and equating coefficients, we get:

-9A + 4A = 1 -9B + 4B = 0

Solving for A and B, we get:

A = -1/5 B = 0

The particular solution is:

y_p = -(1/5) sin(3x)

Step 3: Find the General Solution

The general solution is the sum of the homogeneous solution and the particular solution:

y = y_h + y_p = c1 cos(2x) + c2 sin(2x) - (1/5) sin(3x)

This is the general solution to the differential equation (d2+4)y = sin(3x).

Conclusion

In this article, we have shown how to solve the differential equation (d2+4)y = sin(3x) using the method of undetermined coefficients. The general solution is a linear combination of the homogeneous solution and the particular solution. This equation has many applications in physics and engineering, and its solution is an important tool for modeling real-world systems.

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