tinh tong
2002 2002 2002 -2001 2001 2001 =?
tinh nhanh 2001+2002+1981+2003*21/2003*2002-2001*2002
Tinh nhanh:A=2000*(2001^1999+2001^1998+...+2001^2+2002)+1
Cho A=2002/2001+2001/2002; B= 2000/2001+2001/2002 .So sánh A và B
Giải
Ta có\(A=\frac{2002}{2001}+\frac{2001}{2002}\)và \(B=\frac{2000}{2001}+\frac{2001}{2002}\)
Ta nhận xét thấy A và B cùng có chung 1 số hạng là \(\frac{2001}{2002}\)
Nên ta chỉ so sánh \(\frac{2002}{2001}\)và \(\frac{2000}{2001}\)ta so sánh 2 phân số đó với 1
Vì 2002>2001 nên \(\frac{2002}{2001}\)> 1
Vì 2000<2001 nên \(\frac{2000}{2001}\)<1
\(\Leftrightarrow\)\(\frac{2002}{2001}>\frac{2000}{2001}\)
\(\Leftrightarrow\)\(\frac{2002}{2001}+\frac{2001}{2002}>\frac{2000}{2001}+\frac{2001}{2002}\)
Vậy A>B
A=2000/2001+2001/2002
B=2000+2001/2001+2002
ta có:\(B=\frac{2000+2001}{2001+2002}=\frac{2000}{2001+2002}+\frac{2001}{2001+2002}\)
vì \(\frac{2000}{2001}>\frac{2000}{2001+2002};\frac{2001}{2002}>\frac{2001}{2001+2002}\)
=>A>B
Ta có: B=2000/2001+2002+2001/2001+2002
vì: 2000/2001>2000/2001+2002
2001/2002>2001/2001+2002
nên 2000/2001+2001/2002>2000/2001+2002+2001/2001+2002
Vậy A>B
Chứng minh rằng nếu (a+2002):(a-2002)=(b+2001):(b-2001) với a#0;b#0;b3+-2001 thì a:2002=b:2001
So sánh:
A= 2000/2001 + 2001/2002 với. B=2000+2001/2001+2002
So sanh
A = 2000/2001 +2001/2002
B = 2000+2001/2001+2002
Ta có:
\(A=\frac{2000}{2001}+\frac{2001}{2002}\) và \(B=\frac{2000+2001}{2001+2002}\)
\(\Rightarrow B=\frac{2000}{2001+2002}+\frac{2001}{2001+2002}\)
Ta Xét:
\(\frac{2000}{2001}>\frac{2000}{2001+2002}\)
\(\frac{2001}{2002}>\frac{2001}{2001+2002}\)
\(\Rightarrow\frac{2000}{2001}+\frac{2001}{2002}>\frac{2000}{2001+2002}+\frac{2001}{2001+2002}\)
\(\Rightarrow A>B\)
so sanh :
A=2000/2001+2001/2002
B=2000+2001/2001+2002
\(B=\frac{2000+2001}{2001+2002}=\frac{2000}{2001+2002}+\frac{2001}{2001+2002}
So sánh A và B, biết: A= 2000/2001 + 2001/ 2002 và B= 2000 + 2001/ 2001 + 2002
ta có:\(A=\frac{2000}{2001}+\frac{2001}{2002}<\frac{2000}{2002}+\frac{2001}{2002}=\frac{2000+2001}{2002}<\frac{2000+2001}{2001+2002}=B\)
\(\Rightarrow A
ta có:\(B=\frac{2000+2001}{2001+2002}=\frac{2000}{2001+2002}+\frac{2001}{2001+2002}\)
vì \(\frac{2000}{2001}>\frac{2000}{2001+2002}và\frac{2001}{2002}>\frac{2001}{2001+2002}\)
\(\Rightarrow\frac{2000}{2001}+\frac{2001}{2002}>\frac{2000+2001}{2001+2002}\)
=>A>B