so sánh
\(C=\frac{1999.4001+2000}{2000.4001-2001}\) và \(D=\frac{1501.1503-1500.1498}{6002}\)
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\(\frac{1999.4001+2000}{2000.4001-2001}=\frac{1999.4001+2000}{1999.4001+4001-2001}\)
\(=\frac{1999.4001+2000}{1999.4001+2000}=1\)
(1 - 4x)2n + 3 = 4n + 1
(1 - 4x)2n + 2 = (22)n + 1 = 22n + 2
=>1 - 4x = 2
=> 4x = 1 - 2
=> 4x = -1
=> x = -1/4
Tìm x :
( 1 - 4x )2n+2 = 4n+1
<=> ( 1 - 4x )2n+2 = ( 22 )n+1
<=> ( 1 - 4x )2n+2 = 22n+2
=> 1 - 4x = 2
<=> 4x = 1 - 2
<=> 4x = -1
<=> x = (-1) : 4
<=> x = -1/4
Vaayj x= -1/4
\(\frac{2017^{2000}+2001}{2017^{2017}+2001}\)= \(1\frac{2}{2017^{2017}+2001}\)và \(\frac{2017^{2001}-2000}{2017^{2018}-2000}\)=\(1\frac{2}{2017^{2018}-2000}\)
Vì \(\frac{2}{2017^{2017}+2001}\)<\(\frac{2}{2017^{2018}-2000}\)nên B>A
Ta có: \(\frac{1999x2000}{1999x2000+1}=\frac{1999x2000+1-1}{1999x2000+1}=1-\frac{1}{1999x2000+1}\)
\(\frac{2000x2001}{2000x2001+1}=\frac{2000x2001+1-1}{2000x2001+1}=1-\frac{1}{2000x2001+1}\)
Nhận thấy: \(\frac{1}{1999x2000+1}>\frac{1}{2000x2001+1}\)=> \(1-\frac{1}{1999x2000+1}< 1-\frac{1}{2000x2001+1}\)
=> \(\frac{1999x2000}{1999x2000+1}=\frac{2000x2001}{2000x2001+1}\)
\(\frac{1999x2000}{1999x2000+1}< \frac{2000x2001}{2000x2001+1}\)
Ta có: B = \(\frac{2000+2001}{2001+2002}=\frac{2000}{2001+2002}+\frac{2001}{2001+2002}=\frac{2000}{4003}+\frac{2001}{4003}\)
Ta thấy : \(\frac{2000}{2001}>\frac{2000}{4003}\)(1)
\(\frac{2001}{2002}>\frac{2001}{4003}\) (2)
Từ (1) và (2) cộng vế với vế, ta được :
\(\frac{2000}{2001}+\frac{2001}{2002}>\frac{2000}{4003}+\frac{2001}{4003}\)
hay \(A=\frac{2000}{2001}+\frac{2001}{2002}>B=\frac{2000+2001}{2001+2002}\)
Ta có:
B = \(\frac{2000}{2001+2002}\)+ \(\frac{2001}{2001+2002}\)
Vì \(\frac{2000}{2001}\)> \(\frac{2000}{2001+2002}\)
\(\frac{2001}{2002}\)> \(\frac{2001}{2001+2002}\)
=> \(\left(\frac{2000}{2001}+\frac{2001}{2002}\right)\)> \(\left(\frac{2000}{2001+2002}+\frac{2001}{2001+2001}\right)\)
=> A>B
Vậy A>B
Xét B=\(\frac{2000+2001}{2001+2002}\)\(=\)\(\frac{2000}{2001+2002}\)\(+\)\(\frac{2001}{2001+2002}\)
Mà \(\frac{2000}{2001}>\frac{2000}{2001+2002}\); \(\frac{2001}{2002}>\frac{2001}{2001+2002}\) \(\Rightarrow\)\(\frac{2000}{2001}+\frac{2001}{2002}\)\(>\frac{2000+2001}{2001+2002}\)
Vậy \(A>B\)
\(C=\frac{1999.4001+2000}{2000.4001-2001}\)
\(\Leftrightarrow C=\frac{\left(2000-1\right).4001+2000}{2000.4001-2001}\)
\(\Leftrightarrow C=\frac{2000.4001-4001+2000}{2000.4001-2001}\)
\(\Leftrightarrow C=\frac{2000.4001-2001}{2000.4001-2001}=1\)
\(D=\frac{1501.1503-1500.1498}{6002}\)
\(\Leftrightarrow D=\frac{\left(1502-1\right)\left(1502+1\right)-\left(1499+1\right)\left(1498-1\right)}{6002}\)
\(\Leftrightarrow D=\frac{1502^2-1-1499^2+1}{6002}\)
\(\Leftrightarrow D=\frac{\left(1502-1499\right)\left(1502+1499\right)}{6002}\)
\(\Leftrightarrow D=\frac{3.3001}{6002}=\frac{3.3001}{2.3001}=\frac{3}{2}\)
So sánh 1 và 3/2, Ta thấy C<D
\(C=\frac{\left(3000-1001\right)\left(3000+1001\right)+2000}{2000\left(4001-1\right)+1}\)
\(=\frac{3000^2-1001^2+2000}{2000\cdot4000+1}=\frac{9000000-1002001+2000}{8000000+1}\)
\(=\frac{7999999}{8000001}=0,99999975\)
còn câu D mk làm ở câu khác rồi nên mk ghi luôn kết quả nha
D = 1,5
=> C < D