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

Toán Lớp 6: 2^100 – ( 1 + 2 + 2^2 + 2^3 + -.. + 2^99 )

Toán Lớp 6: 2^100 – ( 1 + 2 + 2^2 + 2^3 + …… + 2^99 )

Comments ( 2 )

  1. Ta có :
    B = 1 + 2 + 2^2 + 2^3 +……+ 2^99
    2B=2+22+23+……+2100
    2B-B=(2+22+23+……+2100)-(1+2+22+23+……+299)
    B=2100-1
    ⇒A-B=2100-2100-1
    ⇒A-B=0-1
     

  2. Giải đáp:
     
    Lời giải và giải thích chi tiết:
    2^100 – ( 1 + 2 + 2^2 + 2^3 + …… + 2^99 )
    Đặt 1 + 2 + 2^2 + 2^3 + …… + 2^99 = B
    Đặt 2^100 = A
    Ta có
    B = 1 + 2 + 2^2 + 2^3 + …… + 2^99
    2B = 2 + 2^2 + 2^3 + …… + 2^100
    2B – B = ( 2 + 2^2 + 2^3 + …… + 2^100 ) – ( 1 + 2 + 2^2 + 2^3 + …… + 2^99 )
    B = 2^100 – 1
    ⇒ A – B = 2^100 – 2^100 – 1
    ⇒ A – B = 0 – 1
    ⇒ A – B = -1

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

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