A.-cos2x
B.cos2x
C.-2cos2x
D.2cos2x
[单选题]设f′(cos2x)=sin2x,则f(x)等于()A . cosx+1/2cos2x+cB . cos2x-1/2cos4x+cC . x+(1/2)x2+cD . x-(1/2)x2+c
[单选题]设y=sin(x-2),则dy=().A.-cosxdxB.cosxdxC.-cos(x-2)dxD.cos(x-2)dx
[单选题]函数y=|π2-x2|sin2x的不可导点个数为( ).A.0B.1C.2D.3
[单选题]函数y=|π2-x2|sin2x的不可导点个数为( ).A.0B.1C.2D.3
[单选题]函数y=|π2-x2|sin2x的不可导点个数为( ).A.0B.1C.2D.3
[单选题]设函数z=x2y,则等于()。A . ['1B . 2C . 1+D . 2+
[单选题]设y=(1+x),则y′(1)等于:()A . 2B . eC . 1/2-ln2D . 1-ln4
[单选题](2009)设z=f(x2-y2),则dz等于:()A . 2x-2yB . 2xdx-2ydyC . f′(x2-y2)dxD . 2f′(x2-y2)(xdx-ydy)
[单选题]设数方组确定了隐函数y=y(x),则等于().A . B . C . D .
[单选题]已知D(X)=2,D(Y)=3,则Cov(X+Y,X-Y)等于().A . 1B . -1C . 5D . 6