www.gusucode.com > symbolic 源码程序 matlab案例代码 > symbolic/SolveASystemOfDifferentialEquations1Example.m
%% Solve a System of Differential Equations %% Code1 % Define the system. syms f(t) g(t) eqn1 = diff(f) == 3*f + 4*g; eqn2 = diff(g) == -4*f + 3*g; S = dsolve(eqn1, eqn2) %% % fSol(t) = S.f gSol(t) = S.g %% % [fSol(t), gSol(t)] = dsolve(eqn1, eqn2) %% % c1 = f(0) == 0; c2 = g(0) == 1; [fSol(t), gSol(t)] = dsolve(eqn1, eqn2, c1, c2) %% Plot1 fplot(fSol) hold on fplot(gSol) grid on legend('fSol','gSol','Location','best') %% Code2 syms x(t) y(t) A = [1 2; -1 1]; B = [1; t]; Y = [x; y]; eqn = diff(Y) == A*Y + B %% % [xSol(t), ySol(t)] = dsolve(eqn) %% % xSol(t) = simplify(xSol(t)) ySol(t) = simplify(ySol(t)) %% % C = Y(0) == [2; -1]; [xSol(t), ySol(t)] = dsolve(eqn, C) %% Plot2 clf fplot(ySol) hold on fplot(xSol) grid on legend('ySol','xSol','Location','best') %% %