释义 |
Ordinary Differential Equation--System with Constant CoefficientsTo solve the system of differential equations
 | (1) |
where is a Matrix and and are Vectors, first consider the homogeneouscase with . Then the solutions to
 | (2) |
are given by
 | (3) |
But, by the Matrix Decomposition Theorem, the Matrix Exponential can be written as
 | (4) |
where the Eigenvector Matrix is
 | (5) |
and the Eigenvalue Matrix is
 | (6) |
Now consider
The individual solutions are then
 | (8) |
so the homogeneous solution is
 | (9) |
where the s are arbitrary constants.
The general procedure is therefore - 1. Find the Eigenvalues of the Matrix
( , ..., ) bysolving the Characteristic Equation. - 2. Determine the corresponding Eigenvectors
, ..., . - 3. Compute
 | (10) |
for , ..., . Then the Vectors which are Real aresolutions to the homogeneous equation. If is a matrix, the Complex vectors correspond to Real solutions to the homogeneous equation given by and . - 4. If the equation is nonhomogeneous, find the particular solution given by
 | (11) |
where the Matrix is defined by
 | (12) |
If the equation is homogeneous so that , then look for a solution of the form
 | (13) |
This leads to an equation
 | (14) |
so is an Eigenvector and an Eigenvalue. - 5. The general solution is
 | (15) |
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