单项选择题
A.(1nx/2)(2+lnx)+c B.x+(1/2)x2+c C.x+ex+c D.ex+(1/2)e2x+c
A.-cosx+c B.cosx+c C.1/2(sin2x/2-x)+c D.1/2(2sin2x-x)+c
A.cosx+1/2cos2x+c B.cos2x-1/2cos4x+c C.x+(1/2)x2+c D.x-(1/2)x2+c