(B) =-dfrac (x)(2)+dfrac (3)(2)-|||-(C) =dfrac (x)(2)+dfrac (3)(2) (D) =-dfrac (x)(2)-dfrac (3)(2)-|||-a-|||-__-|||-C

(B) dfrac (1)(2)(X)_(1)+dfrac (1)(2)(X)_(2)-|||-(C) dfrac (1)(2)(X)_(1)+dfrac (1

dfrac (1)(x) C. -dfrac (1)({x)^2} D. dfrac (2)({x)^3}

dfrac (1)(5)(X)_(1)+dfrac (2)(5)(X)_(2)+dfrac (2)(5)(X)_(3)-|||-D .dfrac (1)(7)(

求椭球面dfrac ({x)^2}(2)+dfrac ({y)^2}(3)+dfrac ({z)^2}(4)=1上点dfrac ({x)^2}(2)+dfrac

已知 f(x)= (B) dfrac {3)(2) (C)2 (D) dfrac (1)(2)

lim _(xarrow 4)dfrac (sqrt {1+2x)-3}(x-4)= (-|||-A dfrac (2)(3) .-|||-B 2-|||-C

函数(x)=dfrac (1)(3)(x)^3+dfrac (1)(2)(x)^2的单调递增区间是( )A．(x)=dfrac (1)(3)(x)^

下列选项中曲面dfrac ({x)^2}(4)+dfrac ({y)^2}(1)+dfrac ({z)^2}(9)=3上点dfrac ({x)^2}(4)+df

直线dfrac (x-1)(2)=dfrac (y)(-1)=dfrac (z-2)(3)-|||-__与直线dfrac (x-1)(2)=dfrac (y)(

3.要使函数φ(x )= ,dfrac {pi )(2)] (B)[π,2π] (C) [ 0,dfrac (pi )(2)] (D) [ dfrac