设=arctan dfrac (x)(y)，则在点(0,1)处的全微分=arctan dfrac (x)(y)__________.

设(X,Y)的分布函数为(x,y)=dfrac (1)({pi )^2}(dfrac (pi )(2)+arctan dfrac (x)(2))(dfrac (

3、设 (x,y)=arctan dfrac (x)(y), 则 (1,1)=-|||-(A)1; (B)0; (C) dfrac {1)(2),dfrac

7.设 =arctan dfrac (1)(x) ,则 dfrac ({d)^2y}(d{x)^2}(x)_(x=1)= __

12.微分方程 (x-arctan y)dfrac (dy)(dx)+1+(y)^2=0 的通解为 ()-|||-(A) =C(e)^arctan y+arct

1.设 sin y+(e)^x-x(y)^2=0, 求 dfrac (dy)(dx).-|||-2.设 ln sqrt ({x)^2+(y)^2}=arctan

(int )_(0)^1arctan dfrac (x)(2)dx=()(int )_(0)^1arctan dfrac (x)(2)dx=()(int )_(

6.求下列各函数的函数值:-|||-(1) (x,y)=([ dfrac {arctan (x+y))(arctan (x-y))] }^2 ,求 (dfrac

(6) arctan dfrac (y)(x)=ln sqrt ({x)^2+(y)^2}

求下列初值问题的解：(dfrac (1+{x)^2}(2))y=arctan x，(dfrac (1+{x)^2}(2))y=arctan x.（ ）求下列初值

二、解答下列各题1.设=arctan dfrac (y)({x)^2}，求dz。二、解答下列各题1.设，求dz。