Page 171 - Schaum's Outline of Differential Equations
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154                   REDUCTION  OF LINEAR  DIFFERENTIAL  EQUATIONS             [CHAP.  17




         17.7.  Put the following  system into the form  of System  (17.7):








                  Since this system contains  a third-order differential  equation in x and a second-order  differential  equation in y,
              we will need  three new x-variables and two new y-variables. Generalizing  Step 2, we define








              Thus,












              or








              These  equations  are equivalent to the matrix equation  x(t)  = A.(t)x(t)  + f(t)  if we define












              Furthermore, if we define  c =  and  = 1, then the initial condition can be given by x(t 0)  = c.
                                           t 0




         17.8.  Put the following  system into the form  of System  (17.7):







                  Since the system contains a second-order  differential  equation in x and a first-order differential  equation in y,
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