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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 9: A=1+2+2 mũ 2+2 mũ 3+-…+2 mũ 50

Toán Lớp 9: A=1+2+2 mũ 2+2 mũ 3+…….+2 mũ 50

Comments ( 2 )

  1. gửi ak!
    A=1+2+2 mũ 2+2 mũ 3+…….+2 mũ 50
    2A=2.(1+2+2 mũ 2+2 mũ 3+…….+2 mũ 50)
    2A=2+2 mũ 2+2 mũ 3+2 mũ 4+…….2 mũ 51
    2A-A=(2+2 mũ 2+2 mũ 3+2 mũ 4+…….2 mũ 51)-(1+2+2 mũ 2+2 mũ 3+…….+2 mũ 50)
    A=2 mũ 51-1
     

  2. $2A=2+2^2+2^3+…+2^{51}$
    $⇒ 2A-A=(2+2^2+2^3+…+2^{51})-(1+2+2^2+2^3+…+2^{50})$
    $⇔ A=2^{51}-1$
     

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222-9+11+12:2*14+14 = ? ( )

About Thúy Mai