A.-cosxdx
B.cosxdx
C.-cos(x-2)dx
D.cos(x-2)dx
[单选题]设y=sin2x,则y′等于().A.-cos2xB.cos2xC.-2cos2xD.2cos2x
[单选题]设y=x-5,则dy=().A.-5dxB.-dxC.dxD.(x-l)dx
[单选题]设y=x(x-1)(x-2)…(x-20),则f ′(0)=( ).A.20! B.0 C.∞ D.-20!
[单选题]设y=f(t),t=φ(x)都可微,则dy=()。A . f'(t)dtB . φ'(x)dxC . f'(t)φ'(x)dtD . f'(t)dx
[单选题]设y=f(t),t=φ(x)都可微,则dy=()。A.f′(t)dtB.φ′(x)dxC.f′(t)φ′(x)dtD.f′(t)dx
[单选题]设y=f(t),t=φ(x)都可微,则dy=()。A.f′(t)dtB.φ′(x)dxC.f′(t)φ′(x)dtD.f′(t)dx
[问答题]设方程x=yy确定y是x的函数,则dy=-----------.
[问答题]设方程x=yy确定y是x的函数,则dy=-----------.
[问答题]设方程x=yy确定y是x的函数,则dy=-------------.
[问答题]设y=f(lnx)ef(x),其中f可微,则dy=-----------.