单项选择题
A.2C1x+C2cosx B.2Cx+cosx C.cosx+C(2x-cosx) D.C(2x-cosx)
A.1/8 B.1/6 C.1/3 D.1/2
A.2yx2y-1 B.x2ylnx C.2x2ylnx D.yx2(y-1)