(B.) y = (1)/(2)x^2e^2x + sin 2x. (C.) y = (x)/(2)(x + 4)e^3x. (D.) y = (x^2cos x + sin 2x)e^3x.

cos 2x(e)^-x+ sin 2x(e)^-xdx-|||-B.cos2xe^(-x)- sin 2x(e)^-xdx-|||-. cos 2x(e)^

(B.)2y_(1)(x)-y_(2)(x)+y_(1)(x)-2y_(4)(x). (C.)2y_(1)(x)-y_(2)(x)+2y_(3)(x)-y_(

微分方程 y-2y+5y=0的通解为y=e^x(C 1cos(2x)+C 2sin(2x))。A. 正确B. 错误

lim _(xarrow 0)dfrac (ln ({sin )^2x+(e)^x)-x}(ln ({x)^2+(e)^2x)-2x}

已知u(x,y)=2x(1-y),则满足u(x,y)=2x(1-y)的解析函数u(x,y)=2x(1-y)为u(x,y)=2x(1-y)u(x,y)=2x(1-

-|||-求函数 (x,y)=(e)^2x(x+2y+(y)^2) 的极值.

已知二阶常系数非齐次线性微分方程有两个特解 y_1 = cos 2x - (1)/(4) x sin 2x，y_2 = sin 2x - (1)/(4) x s

()-|||-A (X)=0, E(Y)=2-|||-B (x)=2, E(Y)=0-|||-C (X)=3, E(Y)=1-|||-D (x)=1 E(Y)=

=(x)^2sin 2x, 求y(50),

=(x)^2sin 2x, 求y(50)