• 2022-06-30
    设 [img=13x19]1803b3595440323.png[/img] 是正向圆周|[img=52x25]1803b3595c0e252.png[/img]. 下列积分中,积分值为零的是( ).
    A: [img=85x48]1803b3596442e07.png[/img]
    B: [img=59x48]1803b3596c9aa00.png[/img]
    C: [img=54x48]1803b359740b59c.png[/img]
    D: [img=83x48]1803b3597bf25c7.png[/img]