cía cn nhok ll kia
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\(P=\dfrac{1}{1007}+\dfrac{1}{1008}+...+\dfrac{1}{2012}+\dfrac{1}{2013}\)
\(=\left(1+\dfrac{1}{2}+...+\dfrac{1}{1006}+\dfrac{1}{1007}+\dfrac{1}{1008}+...+\dfrac{1}{2012}+\dfrac{1}{2013}\right)\)
\(=\left(1+\dfrac{1}{2}+...+\dfrac{1}{1006}\right)\)
\(=\left(1+\dfrac{1}{2}+...+\dfrac{1}{1006}+\dfrac{1}{1007}+\dfrac{1}{1008}+...+\dfrac{1}{2012}+\dfrac{1}{2013}\right)\)
\(=2.\left(\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{6}+...+\dfrac{1}{2012}\right)\)
\(=1-\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{4}+...-\dfrac{1}{2012}+\dfrac{1}{2013}=S\)
Do đó \(\left(S-P\right)^{2013}=0\)
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30000 : 24= 1250 ( đồng)
8 cái bút có số tiền là
1250.8=10000 ( đồng)
vậy............
bạn nói gì vậy