二阶常系数线性微分方程标准形式为
A: y''+P(x)y'+Q(x)=0
B: y''+P(x)y+Q(x)=0
C: x''+P(x)x'+Q(x)x=0
D: x''+P(y)x'+Q(y)x=0
A: y''+P(x)y'+Q(x)=0
B: y''+P(x)y+Q(x)=0
C: x''+P(x)x'+Q(x)x=0
D: x''+P(y)x'+Q(y)x=0
举一反三
- 以下方程为一阶线性微分方程的是 A: y=p(x)y+q(x) B: y'+p(x)y=q(x) C: y''=p(x)y+q(x) D: yy'+x^2=0
- 把 "x ( P( x )®$ y Q( x ,y ))化为前束范式,推导过程正确吗? "x ( P( x )®$y Q( x ,y )) Û"x (¬ P( x ) ∨ $y Q( x ,y )) Û"x$y (¬ P( x ) ∨ Q( x ,y )) Û" x $y ( P( x ) ®Q ( x ,y ))
- 已知y1(x)与y2(x)是方程y″+P(x)y′+Q(x)y=0的两个线性无关的特解,Y1(x)和Y2(x)分别是是方程y″+P(x)y′+Q(x)y=R1(x)和y″+P(x)y′+Q(x)y=R2(x)的特解。那么方程y″+P(x)y′+Q(x)y=R1(x)+R2(x)的通解应是:()
- 设P(x):x是大象,Q(x):x是老鼠,R(x,y):x比y重,则命题“大象比老鼠重”的符号化为 A: ∀x∀y(P(x)∧Q(y)→R(x,y)) B: P(x)∧Q(y)→R(x,y) C: ∀x∃y(P(x)∧Q(y)∧R(x,y)) D: ∃x∃y(P(x)∧Q(y)∧R(x,y))
- 与公式("x)(P(x)∧Q(x, y))Þ($x)R(x, y)等值的是( )。 A: ("x)(P(x)∧Q(x, z))Þ($x)R(x, y) B: ("y)(P(y)∧Q(y, y))Þ($x)R(x, y) C: ("z)(P(z)∧Q(x, y))Þ($x)R(x, y) D: ("u)(P(u)∧Q(u, z))Þ($x)R(x, z)