选择题 1微分方程(x+y)x-)=d+的通解是() (A)x+y+In(x+y=c(B)x-y+In(x+y)=c (C)x+y-In(x+y)=c;(D)x-y-In(x+y)=c 2y2+2y+5y=e^cos2x的特解可设为() (A)y =e Acos 2x; (B)y=xe Acos 2x; (C)y =xe (Acos 2x+Bsin 2x (D)y=e(Acos 2x+ Bsin 2x)
一.选择题 1. 微分方程 (x + y)(dx − dy) = dx + dy 的通解是( ) (A)x + y + ln(x + y) = c; (B)x − y + ln(x + y) = c; (C)x + y − ln(x + y) = c; (D)x − y − ln(x + y) = c. y y y e x x 2. 2 5 cos 2 − + + = 的特解可设为( ) ( ) cos 2 ; * A y e A x − x = ( ) cos 2 ; * B y xe A x − x = ( ) ( cos 2 sin 2 ); * C y xe A x B x x = + − ( ) ( cos 2 sin 2 ). * D y e A x B x x = + −