Question

[Phùng Đức Thịnh]

a, A=1+2+2²+2³+2⁴+2⁵

^{b, B= 10+12+14+...+2010}

Answer 1

[Ngô Long]

a, ta có: 1=2⁰
=>A=2⁰+2^1+2^2+2^3+2^4+2^5
  2A=2+2^2+2^3+2^4+2^5+2^6
  2A-A=2+2^2+2^3+2^4+2^5+2^6-1-2-2^2-2^3-2^4-2^5
       A=2^6-1
      A =64-1
      A =63
b,B=10+12+14+...+2010
     =(2010+10)+(2008+12)+...+(1008+1012)+1010
     =2020+2020+...+2020+1010
         1000 số 2020    ​    

      =2020*1000+1010
      =2020000+1010
      =20201010