  Differential Equations  Definitions for Differential Equations
Function: DESOLVE ([eq1,...,eqn],[var1,...,varn]) where the eq's
are differential equations in the dependent variables
var1,...,varn. The functional relationships must be explicitly
indicated in both the equations and the variables. For example
(C1) 'DIFF(F,X,2)=SIN(X)+'DIFF(G,X); (C2)
'DIFF(F,X)+X^2-F=2*'DIFF(G,X,2); is NOT the proper format.  The
correct way is: (C3) 'DIFF(F(X),X,2)=SIN(X)+'DIFF(G(X),X); (C4)
'DIFF(F(X),X)+X^2-F(X)=2*'DIFF(G(X),X,2); The call is then
DESOLVE([D3,D4],[F(X),G(X)]); If initial conditions at 0 are
known, they should be supplied before calling DESOLVE by using
ATVALUE. (C11) 'DIFF(F(X),X)='DIFF(G(X),X)+SIN(X);
d         d (D11)                   -- F(X) = -- G(X) + SIN(X)
dX        dX (C12) 'DIFF(G(X),X,2)='DIFF(F(X),X)-COS(X);
d          d (D12)                   -- G(X) = -- F(X) - COS(X)
2        dX (C13) ATVALUE('