1.设集合A={x∣1≤x≤2},B={x∣x≥α}。若A⊆B,则α的取值范围是 ( )(A)α<1 (B)α≤1 (C)α<2 (D)α≤22.(理)当z = 时,z100 + z50 + 1的值等于 ( )
A.1 B.– 1 C.i D.– i
(文)已知全集U = {1,2,3,4,5,6,7},A = {3,4,5},B = {1,3,6},则A∩( UB) 等于 ( )
A.{4,5} B.{2,4,5,7} C.{1,6} D.{3}
3.函数y = x2 – 1 (x < 0)的反函数是 ( )
A.y = (x < – 1) B.y = – (x < – 1)
C.y = (x > – 1) D.y = – (x > – 1)
4.函数f (x) = 的图像相邻的两条对称轴之间的距离是 ( )
A. B.5 C. D.