设函数 f(x,y) 具有连续偏导数，满足 f(x,x)=(x+1)^2+(x-2)ln x，且 (partial f)/(partial x)=2(x+1)，则曲线 f(x,y)=0 所围图形绕直线 x=-1 旋转所成旋转体的体积等于 _________.

证明：当 0 < x < pi 时，(x(x+sin x))/(1-cos x) > 4.

5.设二维连续型随机向量(X,Y)的联合概率密度为-|||-f(x,y)= ) (e)^-y,0lt xlt y .-|||-则(X,Y)关于Y的边缘概率密度函数为-|||-(A) _(Y)(y)=y(e)^-y; (B) _(y)(y)=(e)^-y;-|||-(C) _(y)(y)= ) 0,ylt 0 y(e)^-y,ygeqslant 0 .

6.y=arcsin(2+x^2)是否构成函数关系？【2分】A. 不是函数关系B. 无法确定C. 是函数关系D. 与x的取值有关

5.设 ,b,c,mu gt 0 ,曲面 =mu 与曲面 dfrac ({x)^2}({a)^2}+dfrac ({y)^2}({b)^2}+dfrac ({z)^2}({c)^2}=1 相切,则 μ= __

求不定积分int (x)^2(ln x-dfrac (1)(1+{x)^2})dx.

1.设f,φ是C^(2)类类函数, =yf(dfrac (x)(y))+xvarphi (dfrac (y)(x)), 求:(1) a2/ey; (2) dfrac ({partial )^2z}(partial {x)^2}+ydfrac ({partial )^2z}(partial x)

单选题-|||-令 =((alpha )_(1),(alpha )_(2),beta ) =((alpha )_(1),(alpha )_(2),gamma ) 为三阶方阵,且-|||-|A|=1 |B|=2 ,则 |2(alpha )_(1),-(alpha )_(2),gamma -beta |= __-|||-A. -2-|||-B.2-|||-C. -8-|||-D.8

(3)设当x→0时, ^x-(a(x)^2+bx+1) 是比 x^2 高阶的无穷小,则 ()-|||-(A) =dfrac (1)(2) ,b=1 (B) a=1 =1-|||-(C) =-dfrac (1)(2) ,b=-1 (D) a=-1 =1

热门问题