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7 tháng 11 2018

phan h B = (4^32 - 1)(4^32 + 1) = ( 4^16 + 1)(4^32+1)(4^16 - 1)

..... => ket qua

7 tháng 11 2018

Bạn gì ơi mình không hiểu!

21 tháng 7 2021

a) Ta có x + y + z = 0

=> x + y = -z

=> (x + y)3 = (-z)3

=> x3 + y3 + 3xy(x + y) = -z3

=> x3 + y3 + z3 = -3xy(x + y) 

=> x3 + y3 + z3 = -3xy(-z)

=> x3 + y3 + z3 = 3xyz (đpcm) 

14 tháng 7 2019

Ta có: \(A=\left(4+1\right)\left(4^2+1\right)\left(4^4+1\right)\left(4^8+1\right)\left(4^{16}+1\right)\left(4^{32}+1\right)\)

\(\Rightarrow3A=3\left(4+1\right)\left(4^2+1\right)\left(4^4+1\right)\left(4^8+1\right)\left(4^{16}+1\right)\left(4^{32}+1\right)\)

\(\Rightarrow3A=\left(4-1\right)\left(4+1\right)\left(4^2+1\right)\left(4^4+1\right)\left(4^8+1\right)\left(4^{16}+1\right)\left(4^{32}+1\right)\)

\(\Rightarrow3A=\left(4^2-1\right)\left(4^2+1\right)\left(4^4+1\right)\left(4^8+1\right)\left(4^{16}+1\right)\left(4^{32}+1\right)\)

\(\Rightarrow3A=\left(4^4-1\right)\left(4^4+1\right)\left(4^8+1\right)\left(4^{16}+1\right)\left(4^{32}+1\right)\)

\(\Rightarrow3A=\left(4^8-1\right)\left(4^8+1\right)\left(4^{16}+1\right)\left(4^{32}+1\right)\)

\(\Rightarrow3A=\left(4^{16}-1\right)\left(4^{16}+1\right)\left(4^{32}+1\right)\)

\(\Rightarrow3A=\left(4^{32}-1\right)\left(4^{32}+1\right)\)

\(\Rightarrow3A=4^{64}-1\)

mà \(B=4^{64}-1\)

Vậy \(B=3A\)

9 tháng 8 2016

a) \(A=1999\cdot2001=\left(2000-1\right)\left(2000+1\right)=2000^2-1\)

=> \(A< B\)

b) \(A=12^6\)

    \(B=\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\)

       \(=\left(2-1\right)\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\)

      \(=\left(2^2-1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\)

      \(=\left(2^4-1\right)\left(2^4+1\right)\left(2^8+1\right)\)

      \(=\left(2^8-1\right)\left(2^8+1\right)=2^{16}-1\)

=> \(A>B\)

c) \(A=2011\cdot2013=\left(2012-1\right)\left(2012+1\right)=2012^2-1\)

   \(B=2012^2\)

=> \(A< B\)

d) \(A=4\left(3^2+1\right)\left(3^4+1\right)...\left(3^{64}+1\right)\)

        \(=\frac{\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)...\left(3^{64}+1\right)}{2}\)

          \(=\frac{\left(3^4-1\right)\left(3^4+1\right)..\left(3^{64}+1\right)}{2}\)

          \(=\frac{\left(3^8-1\right).....\left(3^{64}+1\right)}{2}\)

           \(=\frac{3^{128}-1}{2}\)

 \(B=3^{128}-1\)

=> \(A< B\)

Cảm ơn bạn 

Bài 2:

a: \(\left(a-b-2\right)^2-\left(2a-2b\right)\left(a-b-2\right)+a^2-2ab+b^2\)

\(=\left(a-b\right)^2-4\left(a-b\right)+4+\left(a-b\right)^2-2\left(a-b\right)\left(a-b-2\right)\)

\(=2\left(a-b\right)^2-4\left(a-b\right)+4-2\left[\left(a-b\right)^2-2\left(a-b\right)\right]\)

\(=2\left(a-b\right)^2-4\left(a-b\right)+4-2\left(a-b\right)^2+4\left(a-b\right)\)

\(=4\)

b: \(\left(2+1\right)\left(2^2+1\right)\cdot...\cdot\left(2^{256}+1\right)-1\)

\(=\left(2^2-1\right)\left(2^2+1\right)\left(2^4+1\right)\cdot...\cdot\left(2^{256}+1\right)-1\)

\(=\left(2^4-1\right)\left(2^4+1\right)\left(2^8+1\right)\cdot...\cdot\left(2^{256}+1\right)-1\)

\(=\left(2^8-1\right)\left(2^8+1\right)\left(2^{16}+1\right)\cdot...\cdot\left(2^{256}+1\right)-1\)

\(=\left(2^{16}-1\right)\left(2^{16}+1\right)\left(2^{32}+1\right)\cdot...\cdot\left(2^{256}+1\right)-1\)

\(=\left(2^{32}-1\right)\left(2^{32}+1\right)\left(2^{64}+1\right)\cdot...\cdot\left(2^{256}+1\right)-1\)

\(=\left(2^{64}-1\right)\left(2^{64}+1\right)\left(2^{128}+1\right)\left(2^{256}+1\right)-1\)

\(=\left(2^{128}-1\right)\left(2^{128}+1\right)\left(2^{256}+1\right)-1\)

\(=\left(2^{256}-1\right)\left(2^{256}+1\right)+1\)

\(=2^{512}-1+1=2^{512}\)

c: \(24\left(5^2+1\right)\left(5^4+1\right)\cdot...\cdot\left(5^{32}+1\right)-5^{64}\)

\(=\left(5^4-1\right)\left(5^4+1\right)\left(5^8+1\right)\left(5^{16}+1\right)\left(5^{32}+1\right)-5^{64}\)

\(=\left(5^8-1\right)\left(5^8+1\right)\left(5^{16}+1\right)\left(5^{32}+1\right)-5^{64}\)

\(=\left(5^{16}-1\right)\left(5^{16}+1\right)\left(5^{32}+1\right)-5^{64}\)

\(=\left(5^{32}-1\right)\left(5^{32}+1\right)-5^{64}\)

=-1

10 tháng 10 2018

\(A=4\left(3^2+1\right)\left(3^4+1\right).....\left(3^{64}+1\right)\)

\(=\frac{1}{2}\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right).....\left(3^{64}+1\right)\)

\(=\frac{1}{2}\left(3^4-1\right)\left(3^4+1\right).....\left(3^{64}+1\right)\)

\(=\frac{1}{2}\left(3^{128}-1\right)< B\)

10 tháng 10 2018

\(A=4\left(3^2+1\right)\left(3^4+1\right)....\left(3^{64}+1\right)\)

\(\Rightarrow2A=\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right).....\left(3^{64}+1\right)\)

\(=\left(3^4-1\right)\left(3^4+1\right).....\left(3^{64}+1\right)=\left(3^{64}-1\right)\left(3^{64}+1\right)=3^{128}-1=B\)

\(\Rightarrow A< B\)

18 tháng 10 2015

Phân tích 3=4-1=\(2^2-1\)

3 tháng 7 2015

tách ít ít ra thôi. để cả cộp thế này k ai làm cho đâu. mệt quá