Consider the DE d²y dy - 18- +81y = x dx² dx which is linear with constant coefficients. First we will work on solving the corresponding homogeneous equation. The auxiliary equation (using m as your variable) is = 0 which has root Because this is a repeated root, we don't have much choice but to use the exponential function corresponding to this root: Y2 = to do reduction of order. Then (using the prime notation for the derivatives) = 3½ = So, plugging y2 into the left side of the differential equation, and reducing, we get y — 18, + 81y2 = So now our equation is eu" = x. To solve for u we need only integrate ace first constant of integration and b as the second we get 9x twice, using a as our u = Therefore y2 = , the general solution. We knew from the beginning that ex was a solution. We have worked out is that re⁹ is another solution to the homogeneous equation, which is generally the case when we have multiple roots. Then 2+9x is the particular solution to the nonhomogeneous equation, and the general solution we derived is pieced together using superposition. 729

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
Question
Consider the DE
d²y
dy
- 18-
+81y = x
dx²
dx
which is linear with constant coefficients.
First we will work on solving the corresponding homogeneous equation. The auxiliary equation (using m
as your variable) is
= 0 which has root
Because this is a repeated root, we don't have much choice but to use the exponential function
corresponding to this root:
Y2 =
to do reduction of order.
Then (using the prime notation for the derivatives)
=
3½
=
So, plugging y2 into the left side of the differential equation, and reducing, we get
y — 18, + 81y2 =
So now our equation is eu" = x. To solve for u we need only integrate ace
first constant of integration and b as the second we get
9x
twice, using a as our
u =
Therefore y2 =
, the general solution.
We knew from the beginning that ex was a solution. We have worked out is that re⁹ is another
solution to the homogeneous equation, which is generally the case when we have multiple roots. Then
2+9x is the particular solution to the nonhomogeneous equation, and the general solution we derived is
pieced together using superposition.
729
Transcribed Image Text:Consider the DE d²y dy - 18- +81y = x dx² dx which is linear with constant coefficients. First we will work on solving the corresponding homogeneous equation. The auxiliary equation (using m as your variable) is = 0 which has root Because this is a repeated root, we don't have much choice but to use the exponential function corresponding to this root: Y2 = to do reduction of order. Then (using the prime notation for the derivatives) = 3½ = So, plugging y2 into the left side of the differential equation, and reducing, we get y — 18, + 81y2 = So now our equation is eu" = x. To solve for u we need only integrate ace first constant of integration and b as the second we get 9x twice, using a as our u = Therefore y2 = , the general solution. We knew from the beginning that ex was a solution. We have worked out is that re⁹ is another solution to the homogeneous equation, which is generally the case when we have multiple roots. Then 2+9x is the particular solution to the nonhomogeneous equation, and the general solution we derived is pieced together using superposition. 729
Expert Solution
steps

Step by step

Solved in 2 steps with 6 images

Blurred answer
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,