令x=2cost,則等于:()
A.-16sin2t·cos2tdt B.-16sin2t·cos2tdt C.16sin2t·cos2tdt D.16sin2t·cos2tdt
設(shè),記F(x)=f(t)dt,0≤x≤2,則在各區(qū)間上F(x)的值()
A.A B.B C.C D.D
A.若f(x)dx=0(a為正常數(shù)),則f(x)必為奇函數(shù) B.在(-∞,+∞)內(nèi)是偶函數(shù) C. D.