方程^2+(y)^2+(z)^2=3xyz确定了隐函数 ^2+(y)^2+(z)^2=3xyz，则^2+(y)^2+(z)^2=3xyz。^2+(y)^2+(z)^2=3xyz^2+(y)^2+(z)^2=3xyz^2+(y)^2+(z)^2=3xyz^2+(y)^2+(z)^2=3xyz

由数字1、2、3、4、5构成的所有排列中，奇排列比偶排列多.

44 填空 (2分) 已知(ax^2y^2-2xy^2)dx+(2x^3y+bx^2y+1)dy为某一函数f(x,y)的全微分，则a=

以下是计算Jf xy^2dxdy的步骤,其中D由曲线-|||-y=4x 与直线 x=1 围成。请选出正确步骤-|||-()-|||-a. iint x(y)^2dxdy=(int )_(0)^1dx(int )_(0)^4xx(y)^2dy-|||-D-|||-b. iint x(y)^2dxdy=(int )_(0)^1dx(int )_(0)^4x(y)^2dy-|||-D-|||-C. dfrac (64)(3)(int )_(0)^1(x)^4dx d. dfrac (64)(3)(int )_(0)^1xdx e. 64/15 f. dfrac (32)(3)-|||-A. a-c-f-|||-B. a-c-e-|||-C. b-c-f-|||-D. b-c-e

以下是求定积分fi xlnxdx的步骤,请把正确步骤-|||-选出并进行排序。 ()-|||-a. (int )_(1)^eln xd(dfrac (1)(2)(x)^2) b. dfrac (1)(2)(x)^2ln x(|)_(1)^e-(int )_(1)^edfrac (1)(2)(x)^2d(ln x)-|||-C. dfrac (1)(2)(x)^2ln x(int )_(1)^e+(int )_(1)^edfrac (1)(2)(x)^2d(ln x) d. dfrac ({e)^2}(2)-dfrac (1)(2)(int )_(1)^exdx-|||-e. dfrac ({e)^2}(2)+dfrac (1)(2)(int )_(1)^exdx f. dfrac (1)(4)((e)^2+1) g. dfrac (1)(4)((e)^2-1)-|||-A. a-c-e-f-|||-B. a-b-d-f-|||-C. -c-e-9-|||-D. a-b-e-f

9. (单选题，5分) int_(L)^ xds=（ ），L为抛物线y=x^2上0≤x≤1的弧段. (A) (1)/(12)(5sqrt(5)-1) (B) (1)/(8)(5sqrt(5)-1) (C) (16)/(3)(5sqrt(5)-1) (D) (1)/(2) A. (A) B. (B) C. (C) D. (D)

列向量组= {alpha )_(1),(alpha )_(2),(alpha )_(3),(alpha )_(4)} 的秩与矩阵= {alpha )_(1),(alpha )_(2),(alpha )_(3),(alpha )_(4)} 的秩相等.( )A.对B.错

用根值审敛法判定下列级数的收敛性:-|||-(1) sum _(n=1)^infty ((dfrac {n)(2n+1))}^n;-|||-(2)-|||-sum _(n=1)^infty dfrac (1)( ln (n+1)] )^n}-|||-(3) sum _(n=1)^infty ((dfrac {n)(3n-1))}^2n-1;-|||-(4) sum _(n=1)^infty ((dfrac {b)({a)_(n)})}^n, 其中 _(n)arrow a(narrow infty ), an,b,a均为正数.

请使用分布函数法计算Z=X+Y的分布函数和密度函数。要求画图，过程写在作业纸上，手写姓名学号，拍照提交。3. 设随机变量(X,Y)的联合概率密度为f(x,y)=}x+y,&0<1,0<1,0,&其他.求Z=X+Y的概率密度.

[题目]将函数 (x)=cos x 展开成 (x+dfrac (pi )(3)) 的幂级数

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