承认自己是数学高手的请进!(初一试题)

5个回答

  • 1.D

    2.设S=2^2+2^3+2^4+2^5+2^6+2^7+2^8+2^9 .(1)

    (1)*2,得

    2S=2^3+2^4+2^5+2^6+2^7+2^8+2^9+2^10 .(2)

    (2)-(1),得

    2S-S=2^10 -2^2

    S=2^10 -2^2

    2-2^2-2^3-2^4-2^5-2^6-2^7-2^8-2^9+2^10

    =2+2^10-(2^2+2^3+2^4+2^5+2^6+2^7+2^8+2^9)

    =2+2^10-(2^10 -2^2)

    =2+2^10-2^10 +2^2

    =6

    3.a=2001×(2002+2002²+.+ 2002^2001)=2001 ×(1-2002*2002)/1-2002-1=2001×(-(2002*2002-1))/-2002=(2002-1)×(2002*2001-1)=2002*2002

    b=2002*2002

    所以a=