Không tính , hãy so sánh :
\(A=\) \(\frac{199}{200}+\frac{200}{201}+\frac{201}{202}\)
\(B=\frac{199+200+201}{200+201+202}\)
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\(\frac{199}{200}>\frac{199}{200+201+202}\)
\(\frac{200}{201}>\frac{200}{200+201+202}\)
\(\frac{201}{202}>\frac{201}{200+201+202}\)
=>\(A>B\)
Do \(\frac{199}{200}\)> \(\frac{199}{200+201+202}\), \(\frac{200}{201}\)>\(\frac{200}{200+201+202}\),\(\frac{201}{202}\)>\(\frac{201}{200+201+202}\)nên A>B
Nếu là so sánh thì B>A vì mỗi phân số của B đều lớn hơn 1 và B nhiều số hạng hơn còn A thì kém về 2 mặt.
Chúc em học tốt^^
Ta có:\(\frac{200}{201}>\frac{200}{201+202}và\frac{201}{202}>\frac{201}{201+202}\)
Suy ra\(\frac{200}{201}+\frac{201}{202}>\frac{200}{201+202}+\frac{201}{201+202}=\frac{200+201}{201+202}\)
Vậy\(\frac{200}{201}+\frac{201}{202}>\frac{200+201}{201+202}\)
200+201/201+202=200/403+201/403
vì 200/201>200/403
201/202>201/403 nên \(\frac{200}{201}+\frac{201}{202}>\frac{200+201}{201+202}\)
\(A=\frac{17^{201}+1}{17^{202}+1}< 1\)
\(\rightarrow A=\frac{17^{201}+1}{17^{202}+1}< \frac{17^{201}+1+16}{17^{202}+1+16}\)
\(\rightarrow A=\frac{17^{201}+1}{17^{202}+1}< \frac{17^{201}+17}{17^{202}+17}\)
\(\rightarrow A=\frac{17^{201}+1}{17^{202}+1}< \frac{17\left(17^{200}+1\right)}{17\left(17^{201}+1\right)}\)
\(\rightarrow A=\frac{17^{201}+1}{17^{202}+1}< \frac{17^{200}+1}{17^{201}+1}\)
\(\rightarrow A=\frac{17^{201}+1}{17^{202}+1}< B\)
\(\rightarrow A< B\)
\(\frac{x+199}{200}+\frac{x+198}{201}+\frac{x+197}{202}=-3\)
\(\frac{x+199}{200}+1+\frac{x+198}{201}+1+\frac{x+197}{202}+1=0\)
\(\frac{x+399}{200}+\frac{x+399}{201}+\frac{x+399}{202}=0\)
\(\left(x+399\right)\left(\frac{1}{200}+\frac{1}{201}+\frac{1}{202}\right)=0\)
Mà \(\left(\frac{1}{200}+\frac{1}{201}+\frac{1}{202}\right)\ne0\)
=> x + 399 = 0
=> x = -399
2009/2010=1-1/2010<1-1/2011=2010/2011
vậy 2009/2010<2010/2011
3^400=(3^4)^100=81^100>64^100=4^300
=>1/3^400<1/4^300
Vậy 1/3^400<1/4^300
\(\frac{200}{201}+\frac{201}{202}>\frac{200}{201+202}+\frac{201}{201+202}=\frac{200+201}{201+202}\)
\(A=\frac{54.107-53}{53.107+54}=\frac{\left(53+1\right)107-53}{53.107+54}=\frac{53.107+107-53}{53.107+54}=\frac{53.107+54}{53.107+54}=1\)
\(B=\frac{135.269-133}{134.269+135}=\frac{\left(134+1\right)269-133}{134.269+135}=\frac{134.269+269-133}{134.269+135}=\frac{134.269+136}{134.269+135}>1\)
Vậy A<B
câu a là
200/201+201/202>200/202+201/202>1
200+201/201+201<1
=>200/201+201/202>1>200+201/201+202
\(A=\frac{199}{200}+\frac{200}{201}+\frac{201}{202}< \frac{199}{200+201+202}+\frac{200}{200+201+202}+\frac{201}{200+201+202}\)
A \(< \frac{199+200+201}{200+201+202}=B\)
\(A< B\)
Ta có: \(A=\frac{199}{200}+\frac{200}{201}+\frac{201}{202}< \frac{199}{200+201+202}+\frac{200}{200+201+202}+\frac{201}{200+201+202}< \)
\(< \frac{199+200+201}{200+201+202}\)
Vậy A < B
ỦNG HỘ TỚ NHA