so sánh A=5^32 -1 và B = (5^2-4.5+1)(5^2+1)(5^4 +1)(5^8+1)(5^16+1)
So sánh A=532 và B=24(5^2+1)(5^4+1)(5^8+1)(5^16+1)
B=24(5^2+1)(5^4+1)(5^8+1)(5^16+1)
=(5^2-1)(5^2+1)(5^4+1)(5^8+1)(5^16+1)
=(5^4-1)(5^4+1)(5^8+1)(5^16+1)
=(5^8-1)(5^8+1)(5^16+1)
=(5^16-1)(5^16+1)
=5^32-1
Vậy B<A
so sánh 12(5^2+1)(5^4+1)(5^8+1)(5^16+1)(5^32+1) và 5^64-1
\(12\left(5^2+1\right)\left(5^4+1\right)\left(5^8+1\right)\left(5^{16}+1\right)\left(5^{32}+1\right)\)
\(=\frac{1}{2}\left(5^2-1\right)\left(5^2+1\right)\left(5^4+1\right)\left(5^8+1\right)\left(5^{16}+1\right)\left(5^{32}+1\right)\)
\(=\frac{1}{2}\left(5^4-1\right)\left(5^4+1\right)\left(5^8+1\right)\left(5^{16}+1\right)\left(5^{32}+1\right)\)
\(=\frac{1}{2}\left(5^8-1\right)\left(5^8+1\right)\left(5^{16}+1\right)\left(5^{32}+1\right)\)
\(=\frac{1}{2}\left(5^{16}-1\right)\left(5^{16}+1\right)\left(5^{32}+1\right)\)
\(=\frac{1}{2}\left(5^{32}-1\right)\left(5^{32}+1\right)\)
\(=\frac{1}{2}\left(5^{64}-1\right)\)
B=24(52+1)(54+1)(58+1)(516+1), và N=532. So sánh B với N
SO SÁNH A VÀ B BIẾT :\(A=5^{32}\)
VÀ \(B=24\left(5^2+1\right)\left(5^4+1\right)\left(5^8+1\right)\left(5^{16}+1\right)\)
\(B=24\left(5^2+1\right)\left(5^4+1\right)\left(5^8+1\right)\left(5^{16}+1\right)\)
\(=\left(5^2-1\right)\left(5^2+1\right)\left(5^4+1\right)\left(5^8+1\right)\left(5^{16}+1\right)\)
\(=\left(5^4-1\right)\left(5^4+1\right)\left(5^8+1\right)\left(5^{16}+1\right)\)
\(=\left(5^8-1\right)\left(5^8+1\right)\left(5^{16}+1\right)\)
\(=\left(5^{16}-1\right)\left(5^{16}+1\right)\)
\(=5^{32}-1< 5^{32}\)
Vậy \(B< A\)
Bài 1 So sánh
A= 40+ 3/8 + 7/8^2 + 5/8^3 + 32/8^5
B= 24/8^2 + 40 + 5/8^2 + 40/8^4 + 5/8^4
Bài 2 So sánh
a, 1.3.5.7...99 và 51/2 . 52/2 .... 100/2
b, A= 1+1/2 + 1/3 + 1/4 + ...... + 1/64 và 4
Bài1:So sánh
A=2006/987654321+2007/246813579
B=2007/987654321+2006/246813579
b)1965/1976 và 1973/1975
Bài2:Tìm x
a)3 - (5 và 3/8 + x - 7 và 5/24):6 và 2/3=2
b) (1/1*2+1/2*3+1/3*4+1/4*5+1/5*6)*10 - x=0
Bài3:Tính nhanh
A=1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/256
1. 2006/987654321 + 2007/246813579 = 2007/246813579 + 2006/987654321
=>
2.
3 - (5.3/8 + X - 7 . 5/24) : 6 . 2/3 =2
3 - (15/8 + X - 35/24) : 4 = 2
3 - (15/8 + X - 35/24) = 2 . 4
3 - (15/8 + X - 35/24) = 8
15/8 + X - 35/24 = 3 - 8
15/8 + X - 35/24 = -5
15/8 + X = -5 + 35/24
15/8 + X = -85/24
X = -85/24 - 15/8
X = -65/12
Cho A=(5+1)(5^2+1)(5^4+1)(5^8+1)(5^16+1)(5^32+1) và B=1/5(5^64-1) S^2 A và B
\(A=\left(5+1\right)\left(5^2+1\right)\left(5^4+1\right)\left(5^8+1\right)\left(5^{16}+1\right)\left(5^{32}+1\right)\)
\(4A=\left(5-1\right)\left(5+1\right)\left(5^2+1\right)\left(5^4+1\right)\left(5^8+1\right)\left(5^{16}+1\right)\left(5^{32}+1\right)\)
\(4A=\left(5^2-1\right)\left(5^2+1\right)\left(5^4+1\right)\left(5^8+1\right)\left(5^{16}+1\right)\left(5^{32}+1\right)\)
\(4A=\left(5^4-1\right)\left(5^4+1\right)\left(5^8+1\right)\left(5^{16}+1\right)\left(5^{32}+1\right)\)
...
\(4A=5^{64}-1\)
\(\Rightarrow A=\frac{5^{64}-1}{4}>B=\frac{5^{64}-1}{5}\)
cho biểu thức A=(1/1.2+1/2.3+1/3.4+1/4.5+........+ 1/2016.2017): 2 Hãy so sánh A với 1/2
Cho biểu thức B= 1/31+1/32+1/33+1/34+........+1/60. Hãy chứng tỏ 3/5<B<4/5
\(A=\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{2016.2017}\right):2\)
\(=\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{2016}-\frac{1}{2017}\right):2\)
\(=\left(1-\frac{1}{2017}\right):2\)\(< \)\(\frac{1}{2}\) (Do 1 - 1/2017 < 1)
Cho M=24(52+1)(54+1)(58+1)(516+1)
N=532
So sánh M và N