Cho A = (3 + 1 ).(3^2 + 1 ).(3^4 + 1 ).(3^8 + 1 ).(3^16 + 1 )
B = (3^32 - 1 ) .Khi đó, B = k.A
Vậy k =?
Cho A=(3 + 1)(32 +1)(34 +1)(38+1)(316 +1)
B=332 - 1 nếu B = k.A thì k=?
A=(3+1)(32+1)(34+1)(38+1)(316+1)
=>2A=(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=B
=>B=1.A
=>k=1
Vậy k=1
Ta có :A=(3+1)(32+1)(34+1)(38+1)(316+1)
2A=2.(3+1)(32+1)(34+1)(38+1)(316+1)
2A=(3-1)(3+1)(32+1)(34+1)(38+1)(316+1)
2A=(32-1)(32+1)(34+1)(38+1)(316+1)
2A=(34-1)(34+1)(38+1)(316+1)
2A=(38-1)(38+1)(316+1)
2A=(316-1)(316+1)
2A=332-1
Lại có :B=332-1 =2A =>k=2
Chứng minh rằng: A>B khi:
A=(3+1)(3^2+1)(3^4+1)(3^6+1)(3^8+1)(3^16+1) B=3^32 -1
1.Chứng minh rằng a)1/2-1/4+1/8-1/16+1/32-1/64<1/3 b)1/3-2/3^2+3/3^3-4/3^4+...+99/3^99-100/3^100<3/16
A=3^32-1 và B=(3-1)(3^2-1)(3^4-1)(3^8-1)(3^16-1)
CMR:
a)1/2-1/4+1/8-1/16+1/32-1/64<1/3
b)1/3 - 2/3^2 + 3/3^3 - 4/3^4 +...+ 99/3^99 -100/3^100 < 3/16
cmr
a) 1/2 -1/4+1/8-1/16+1/32-1/64 <1/3
b) 1/3-2/3^2+3/3^3-4/3^4+...+99/3^99-100/3^100<3/16
A= 4 x ( 3^2+1 ) x ( 3^4+1 ) x ( 3^8+1 ) x ( 3^16+1 ) và B= 3 ^32 -1
Có: \(A=4\cdot\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)
\(=\frac{1}{2}\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)
\(=\frac{\left(3^4-1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)}{2}\)
\(=...........................\)
\(=\frac{3^{32}-1}{2}\)
\(B=3^{32-1}\)
=> \(A< B\)
So sánh A và B: A=(43^2+1)(3^4+1)(3^8+1)(3^16+1); B=3^32-1
So sánh 2 số A và B biết :
A = (3+1)(2^2+1)(3^4+1)(3^8+1)(3^16+1) và B = 3^32 - 1
Mình ghi nhầm đề bài 1 tí đề bài là :
So sánh 2 số A và B biết :
A = (3+1)(3^2+1)(3^4+1)(3^8+1)(3^16+1) và B = 3^32 - 1
A = (2-1)(2+1)(2^2 + 1 ) (2^4 + 1 ) ( 2^8 + 1) ( 2^16 + 1)
A = (2^2 - 1)(2^2 + 1 ) ( 2^4 + 1 )(2^8 + 1 )(2^16 + 1)
A= ( 2^4 - 1 )( 2^4 + 1 )(2^8 + 1 )(2^16 + 1 )
A = (2^8 - 1 )(2^8 + 1 )(2^16 + 1 )
A = (2^16 - 1 )(2^16 + 1 )
A = 2^32 - 1 < 2^32 = B
Vậy A = B
k mik nka !