[名词解释] 亦步亦趋yì bù yì qū
[名词解释] 鱼鳍yú qí :鳍(qí)
[名词解释] 良莠不齐liánɡ yǒu bù qí
[名词解释] 颐指气使 yí zhǐ qì shǐ
[名词解释] 轻盈qīnɡ yínɡ
[名词解释] 颐指气使yí zhǐ qì shǐ
[单选题]已知y1(x)与y2(x)是方程y″+P(x)y′+Q(x)y=0的两个线性无关的特解,Y1(x)和Y2(x)分别是是方程y″+P(x)y′+Q(x)y=R1(x)和y″+P(x)y′+Q(x)y=R2(x)的特解。那么方程y″+P(x)y′+Q(x)y=R1(x)+R2(x)的通解应是:()A . c1y1+c2y2B . c1Y1(x)+c2Y2(x)C . c1y1+c2y2+Y1(x)D . c1y1+c2y2+Y1(x)+Y2(x)
[单选题]设线性无关函数y1、y2、y3都是二阶非齐次线性方程y″+P(x)y′+Q(x)y=f(x)的解,c1、c2是待定常数。则此方程的通解是:()A . c1y1+c2y2+y3B . c1y1+c2y2-(c1+c3)y3C . c1y1+c2y2-(1-c1-c2)y3D . c1y1+c2y2+(1-c1-c2)y3