Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2
Cmr C=1\3+1\32+1\33+.....+1\32005nho hơn 1\2.
Theo đầu bài, số a có dạng:
\(a=3k+1\Rightarrow a+2=3\left(k+1\right)\)
\(a=4r+2\Rightarrow a+2=4\left(r+1\right)\)
\(a=5x+3\Rightarrow a+2=5\left(x+1\right)\)
\(a=6y+4\Rightarrow a+2=6\left(y+1\right)\)
\(\Rightarrow a+2=BCNN\left\{3;4;5;6\right\}\cdot z=60z\)
Vậy dạng chung của a là 60z - 2