\(y=\frac{198\cdot199-200}{196+197\cdot198}\)
A=\(\frac{1}{199}-\frac{1}{199\cdot198}-\frac{1}{198-197}-\frac{1}{197-196}-...-\frac{1}{3.2}-\frac{1}{2.1}\)
Đề mk chắc là sai đó bn !!
Bn kiểm tra lại xem
Nhớ đúng mk nha
\(\frac{198\cdot199-200}{198\cdot197-200}\)
=\(\frac{198.199-200}{198.197-200}\)
=\(\frac{1.199-200}{1.197-200}\)
=\(\frac{199-200}{197-200}\)
=\(\frac{-1}{-3}\)
cho A=\(\frac{196}{197}+\frac{197}{198};B=\frac{196+197}{197+198}.TronghaisốAvàB,sốnàolớnhơn\)
Ta có : A=\(\frac{196}{197}\)+\(\frac{197}{198}\)>\(\frac{196}{198}+\frac{197}{198}\)
\(\frac{196+197}{198}\)>B=\(\frac{197+197}{197+198}\)
Vậy A>B
Ta có: B=\(\frac{196+197}{197+198}=\frac{196}{197+198}+\frac{197}{197+198}\)
Mà \(\frac{196}{197}>\frac{196}{197+198};\frac{197}{198}>\frac{197}{197+198}=>\frac{196}{197}+\frac{197}{198}>\frac{196}{197+198}+\frac{197}{197+198}\)
=> A>B
cho \(A=\frac{196}{197}+\frac{197}{198}\)và \(B=\frac{196+197}{197+198}\)
Ta có :
\(B=\frac{196+197}{197+198}=\frac{196}{197+198}+\frac{197}{197+198}\)
Vì :
\(\frac{196}{197}>\frac{196}{197+198};\frac{197}{198}>\frac{197}{197+198}\)
=> A > B
=))
ta có:
\(B=\frac{196+197}{197+198}=\frac{196}{197+198}+\frac{197}{197+198}\)
Mà: \(\frac{196}{197+198}< \frac{196}{197}\)
\(\frac{197}{197+198}< \frac{197}{198}\)
=> \(\frac{196}{197}+\frac{197}{198}>\frac{196+197}{197+198}\)
Vậy:\(A>B\)
A>1 B<1
Vậy A>B
198*199-200/196+197*198
198*199-200/196+197*198
cho \(A=\frac{196}{197}+\frac{197}{198}=\frac{196+197}{197+198}\)so sánh A và B
Ta có:
\(\frac{196}{197+198}<\frac{196}{197}\)
\(\frac{197}{197+198}<\frac{197}{198}\)
\(\Rightarrow\frac{196}{197+198}+\frac{197}{197+198}<\frac{196}{197}+\frac{197}{198}\left(1\right)\)
Mà \(B=\frac{196+197}{197+198}=\frac{196}{197+198}+\frac{197}{197+198}\left(2\right)\)
Từ ( 1 ) và ( 2 )
\(\Rightarrow B<\frac{196}{197}+\frac{197}{198}\)
\(\Rightarrow B
Gọi 196/197 là a/c, 197/198 la b/d
Có a/c+b/d=a+b/c+d( tính chất của dãy tỉ số bằng nhau)
\(A=\frac{196}{197}+\frac{197}{198}\) \(B=\frac{196+197}{197+198}\)
\(A=\frac{196}{197}+\frac{197}{198}\) \(B=\frac{196}{197+198}+\frac{197}{197+198}\)
Ta có: \(\frac{196}{197}>\frac{196}{197+198}\) vì \(197<197+198\)
\(\frac{197}{198}>\frac{197}{197+198}\) vì \(198<197+198\)
\(\Rightarrow\)\(\frac{196}{197}+\frac{197}{198}\) \(>\frac{196}{197+198}+\frac{197}{197+198}\)
\(\Leftrightarrow\)\(\frac{196}{197}+\frac{197}{198}\)\(>\)\(\frac{196+197}{197+198}\)
Vậy \(A>B\)
198*199-200 phan 196+197*198
Cho A = \(\frac{196}{197}+\frac{197}{198}\)và B = \(\frac{196+197}{197+198}\)So sánh A và B
\(A>B\)
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\(A>\frac{196}{198}+\frac{197}{198}=\frac{196+197}{198}>\frac{196+197}{197+198}=B\)
=>A>B
vậy...