用常数变易法：假设微分方程L(y)=0的基本解是y1,y2,...,yn,要求L(y)=g(x)的通解就设通解是y=u1y1+u2y2+...+unyn (ui=ui(x))而且满足W(y1,y2,...,yn)*(u1',u2',...,un')^T=(0,0,...,0,g(x))^T （W表示wrongskian；右...