(1)已知集合U={1,2,3,4,5,6,7},A= {2,4,5,7},B = {3,4,5},則(CUA)∪(CUB)=
(A){1,6} (B){4,5}
(C){2,3,4,5,7} (D){1,2,3,6,7}
(2)在等差數(shù)列{a n}中,若a4+ a6=12,Sn是數(shù)列{a n}的前n項(xiàng)和,則S9的值為
(A)48 (B)54 (C)60 (D)66
(3)過坐標(biāo)原點(diǎn)且與圓相切的直線的方程為
(A)y =-3x 或 (B)y = 3x 或
(C)y =-3x或 (D)y = 3x 或
(4)對(duì)于任意的直線l與平面α,在平面α內(nèi)必有直線m,使m與l
(A)平行 (B)相交
(C)垂直 (D)互為異面直線
(5)若的展開式中各項(xiàng)系數(shù)之和為64,則展開式的常數(shù)項(xiàng)為