極限()
A.-1 B.0 C.1 D.2
等于下列哪個函數(shù)()?
A.[f(x)+f(x-A.]dx B.[f(x)+f(a-x)]dx C.[f(x)-f(a-x)]dx D.[f(x)-f(x-A.]dx
設函數(shù),則Q′(x)等于:()
A.xe-x B.-xe-x C. D.-