CMR
\(2008^{100}+2008^{99}⋮2009\)
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Ta có:
2008100+200899
= 200899.2008+200899
= 200899.(2008+1)
= 200899.2009
Vì 2009 chia hết cho 2009 => 200899.2009 chia hết cho 2009 => 2008100+200899 chia hết cho 2009
2008100 + 200899 = 200899(2008+1) = 200899. 2009
=> 2008100 + 200899 chia hết cho 2009
Ta có :
\(2008^{100}+2008^{99}\)
\(=2008^{99}.\left(2008+1\right)\)
\(=2008^{99}.2009⋮2009\)
=> đpcm
Học tốt
\(2008^{99}\cdot2008+2008^{99}\)
\(=2008^{99}\cdot\left(2008+1\right)\)
\(=2008^{99}.2009⋮2009\left(dpcm\right)\)
\(2008^{100}+2008^{99}=2008^{99}.\left(2008+1\right)=2008^{99}.2009⋮2009\) ( đpcm )
\(2008^{100}+2008^{99}\)
\(=2008^{99}.\left(2008+1\right)\)
\(=2008^{99}.2009⋮2009\)
=> đpcm
a) Áp dụng \(\frac{a}{b}< 1\Leftrightarrow\frac{a}{b}< \frac{a+m}{b+m}\) (a;b;m \(\in\) N*)
Ta có:
\(A=\frac{2008^{2008}+1}{2008^{2009}+1}< \frac{2008^{2008}+1+2007}{2009^{2009}+1+2007}\)
\(A< \frac{2008^{2008}+2008}{2008^{2009}+2008}\)
\(A< \frac{2008.\left(2008^{2007}+1\right)}{2008.\left(2008^{2008}+1\right)}=\frac{2008^{2007}+1}{2008^{2008}+1}=B\)
=> A < B
b) Áp dụng \(\frac{a}{b}>1\Leftrightarrow\frac{a}{b}>\frac{a+m}{b+m}\) (a;b;m \(\in\) N*)
Ta có:
\(N=\frac{100^{101}+1}{100^{100}+1}>\frac{100^{101}+1+99}{100^{100}+1+99}\)
\(N>\frac{100^{101}+100}{100^{100}+100}\)
\(N>\frac{100.\left(100^{100}+1\right)}{100.\left(100^{99}+1\right)}=\frac{100^{100}+1}{100^{99}+1}=M\)
=> M > N
a) Ta có:
\(2008^{100}+2008^{99}\)
\(=2008^{99}.\left(2008+1\right)\)
\(=2008^{99}.2009\)
Vì \(2009⋮2009\) nên \(2008^{99}.2009⋮2009.\)
\(\Rightarrow2008^{100}+2008^{99}⋮2009.\)
b) Ta có:
\(12345^{678}-12345^{677}\)
\(=12345^{677}.\left(12345-1\right)\)
\(=12345^{677}.12344\)
Vì \(12344⋮12344\) nên \(12345^{677}.12344⋮12344.\)
\(\Rightarrow12345^{678}-12345^{677}⋮12344.\)
Chúc bạn học tốt!
\(2008^{100}\cdot2008^{99}\)
\(=2008^{99}\left(2008+1\right)\)
\(=2008^{99}\cdot2009⋮2009\left(đpcm\right)\)
\(=2008^{99}.2008+2008^{99}.1\)
\(=2008^{99}.\left(2008+1\right)\)
\(=\left(2008^{99}.2009\right)⋮2009\)
\(\Rightarrow2008^{100}+2008^{99}⋮2009\)