so sánh (-1/3)^500 với (-1/5)^300
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![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
(-1/5)^300= [(-1/5)^3]^100=(1/125)^100
(-1/3)^500=[(-1/3)^5]^100=(1/243)^100
k mik tròn 45 nhé
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta có :
\(-\left(\frac{1}{3}\right)^{500}=-\left(\frac{1}{3}\right)^{5.100}=\) \(-\left(\frac{1}{243}\right)^{100}\)
\(-\left(\frac{1}{5}\right)^{300}=-\left(\frac{1}{5}\right)^{3.100}\) =\(-\left(\frac{1}{125}\right)^{100}\)
Vì \(-\left(\frac{1}{125}\right)< -\left(\frac{1}{243}\right)\)nên \(-\left(\frac{1}{3}\right)^{500}>-\left(\frac{1}{5}\right)^{300}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
(-1/3)^500 >(-1/3)^300 . Vì 500 > 300 (so sánh 2 lũy thừa cùng cơ số , số nào có số mũ lớn hơn thì số đó lớn hơn và ngược lại)
Ta có :
\(\left(\frac{-1}{3}\right)^{500}=\left(\frac{1}{3}\right)^{500}\)
\(\left(\frac{-1}{3}\right)^{300}=\left(\frac{1}{3}\right)^{300}\)
Vì 500 > 300
=> \(\left(\frac{1}{3}\right)^{500}< \left(\frac{1}{3}\right)^{300}\)
=> \(\left(\frac{-1}{3}\right)^{500}< \left(\frac{-1}{3}\right)^{300}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta có :
\(\frac{1^{500}}{2}=\frac{1}{2}\)
\(\frac{1^{300}}{3}=\frac{1}{3}\)
Mà 3>2
\(\Rightarrow\frac{1}{2}>\frac{1}{3}\)
Hay \(\frac{1^{500}}{2}>\frac{1^{300}}{3}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\left(\frac{1}{3}\right)^{500}=\left(\frac{1}{3}^5\right)^{100}=\frac{1}{243}^{100}\)
\(\left(\frac{1}{5}\right)^{300}=\left(\frac{1}{5}^3\right)^{100}=\frac{1}{125}^{100}\)
Vì \(\frac{1}{243}<\frac{1}{125}=>\frac{1}{243}^{100}<\frac{1}{125}^{100}=>\left(\frac{1}{3}\right)^{500}<\left(\frac{1}{5}\right)^{300}\)
3-500=(35)-100= 243-100
5-300= (53)-100 =125-100
243>125 => 243-100<125-100
Hay 3-500 <5-300
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\left(-\frac{1}{5}\right)^{300}=-\frac{1^{300}}{5^{300}}=-\frac{1}{5^{300}}\)
\(\left(-\frac{1}{5}\right)^{500}=-\frac{1^{500}}{5^{500}}=-\frac{1}{5^{500}}\)
Ta có :
\(5^{300}< 5^{500}\)
\(\Rightarrow-5^{300}>-5^{500}\)
\(\Rightarrow-\frac{1}{5^{300}}>-\frac{1}{5^{500}}\)
\(\Rightarrow\left(-\frac{1}{5}\right)^{300}>\left(-\frac{1}{5}\right)^{500}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta co : 3500 va -5300
=>3500=(35)100=243100 (1)
=>-5300=(-53)100=-125100 (2)
Tu (1) va (2) suy ra 3500>-5300
lik e nhe
3500 và -5300
3500 = ( 3 5 ) 100 = 243100
-5300 = ( -5 3)100 = -125100
do 243 > -125 nên => 243100 > -125100
=> 3500 > -5300
tick nhé
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta có:
(-1/5)300 = (-1)300/5300 = 1/(53)100 = 1/125100
(-1/3)500 = (-1)500/3500 = 1/(35)100 = 1/243100
Vì 125100 < 243100
=> 1/125100 > 1/243100
=> (-1/5)300 > (-1/3)500
Ta có : \(\left(-\frac{1}{5}\right)^{300}=\left(-\frac{1}{5}\right)^{3.100}=\left(-\frac{1}{125}\right)^{100}=\left(\frac{1}{125}\right)^{100}\)
\(\left(-\frac{1}{3}\right)^{500}=\left(-\frac{1}{3}\right)^{5.100}=\left(-\frac{1}{243}\right)^{100}=\left(\frac{1}{243}\right)^{100}\)
Mà \(125< 243\Rightarrow\frac{1}{125}>\frac{1}{243}\Rightarrow\left(\frac{1}{125}\right)^{100}>\left(\frac{1}{243}\right)^{100}\)
\(=>\left(-\frac{1}{5}\right)^{300}>\left(-\frac{1}{3}\right)^{500}\)
Ta có:
\(\left(\dfrac{-1}{3}\right)^{500}=\left(\dfrac{1}{3}\right)^{500}=\dfrac{1}{3^{500}}=\dfrac{1}{3^{5^{100}}}=\dfrac{1}{243^{100}}\)
\(\left(\dfrac{-1}{5}\right)^{300}=\left(\dfrac{1}{5}\right)^{300}=\dfrac{1}{5^{300}}=\dfrac{1}{5^{3^{100}}}=\dfrac{1}{125^{100}}\)
Vì 243100 > 125100 nên \(\dfrac{1}{243^{100}}\) < \(\dfrac{1}{125^{100}}\). \(\Rightarrow\) \(\left(\dfrac{-1}{3}\right)^{500}\)< \(\left(\dfrac{-1}{5}\right)^{300}\)
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