A:7
B:398
C:889
D:1859
- The storybook is very interesting.
- I agree with you. I ______ it twice already.
用数学归纳法证明:1+122+132+⋯+12n2<2-12nn∈N*,第二步证明“从k到k+1”,左端增加的项数是( )
已知全集U=R,集合A=y|y=x2,集合B=y|y=2x,则A∩CUB为( )。