Question

So sanh 2 so sau:

A=3³² -1

B=(3+1) .(3² +1) .(3⁴ +1) . (3⁸ +1) .(3¹⁶ +1)

Answer 1

  B = (3 + 1).(3² + 1).(3⁴ + 1).(3⁸ + 1).(3¹⁶ + 1)

2B = (3 - 1).(3 + 1).(3² + 1).(3⁴ + 1).(3⁸ + 1).(3¹⁶ + 1)

     = (3² - 1).(3² + 1).(3⁴ + 1).(3⁸ + 1).(3¹⁶ + 1)

     = (3⁴ - 1).(3⁴ + 1).(3⁸ + 1).(3¹⁶ + 1)

     = (3⁸ - 1).(3⁸ + 1).(3¹⁶ + 1)

     = (3¹⁶ - 1).(3¹⁶ + 1)

     = 3³² - 1

Vậy A = B

Answer 2

lộn r` bn B = 3³²-1 / 2

Vậy A > B