1.下列运算正确的是( )
A.(ax2-bx+c)′=a(x2)′+b(-x)′
B.(sinx-2x2)′=(sinx)′-(2)′(x2)′
C.(cosx·sinx)′=(sinx)′·cosx+(cosx)′·cosx
D.[(3+x2)(2-x3)]′=2x(2-x3)+3x2(3+x2)
答案: A
2.设y=-2exsin x,则y′等于( )
A.-2excos x B.-2exsin x
C.2exsin x D.-2ex(sin x+cos x)
解析: y′=-2(exsin x)′=-2[(ex)′sin x+ex(sin x)′]
=-2[exsin x+excos x]
=-2ex(sin x+cos x).