11-2 复数的概念与运算
1.(2011•福建理,1)i是虚数单位,若集合S={-1,0,1},则( )
A.i∈S B.i2∈S
C.i3∈S D.2i∈S
[答案] B
[解析] i2=-1∈S,故选B.
2.(文)(2011•天津文,1)i是虚数单位,复数1-3i1-i=( )
A.2-i B.2+i
C.-1-2i D.-1+2i
[答案] A
[解析] 1-3i1-i=1-3i1+i1-i1+i=4-2i2=2-i.
(理)(2011•安徽皖南八校联考)复数z满足z=2-i1-i,则z-等于( )
A.1+3i B.3-i
C.32-12i D.12+32i
[答案] C
[解析] ∵z=2-i1-i=2-i1+i2=3+i2,
∴z-=32-12i,故选C.