【高中数学证明题一道】设a1>a2>…>an>an+1,求证1/(a1-a2)+1/(a2-a3)+…+1/(an-an+1)+1/(an+1-a1)>0.设a1>a2>…>an>an+1,求证1/(a1-a2)+1/(a2-a3)+…+1/(an-an+1)+1/(an+1-a1)>0.最好能用上柯西不等式或均值不等式。
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【高中数学证明题一道】设a1>a2>…>an>an+1,求证1/(a1-a2)+1/(a2-a3)+…+1/(an-an+1)+1/(an+1-a1)>0.设a1>a2>…>an>an+1,求证1/(a1-a2)+1/(a2-a3)+…+1/(an-an+1)+1/(an+1-a1)>0.最好能用上柯西不等式或均值不等式。
【高中数学证明题一道】设a1>a2>…>an>an+1,求证1/(a1-a2)+1/(a2-a3)+…+1/(an-an+1)+1/(an+1-a1)>0.
设a1>a2>…>an>an+1,求证1/(a1-a2)+1/(a2-a3)+…+1/(an-an+1)+1/(an+1-a1)>0.
最好能用上柯西不等式或均值不等式。
【高中数学证明题一道】设a1>a2>…>an>an+1,求证1/(a1-a2)+1/(a2-a3)+…+1/(an-an+1)+1/(an+1-a1)>0.设a1>a2>…>an>an+1,求证1/(a1-a2)+1/(a2-a3)+…+1/(an-an+1)+1/(an+1-a1)>0.最好能用上柯西不等式或均值不等式。
因为 1/(an+1-a1)+1/(a1-an+1)=0
所以 只需证明 1/(a1-a2)+1/(a2-a3)+...+1/(an-an+1)>1/(a1-an+1)
因为a1>a2>a3...>an>an+1
所以 a1>an
a1-an+1>an-an+1>0
1/(an-an+1)>1/(a1-an+1)
所以 1/(a1-a2)+1/(a2-a3)+...+1/(an-an+1)>1/(an-an+1)>1/(a1-an+1)
所以 1/(a1-a2)+1/(a2-a3)+...+1/(an-an+1)+1/(an+1-a1)>0
a1>a2>a3...>an>an+1
所以
a1>an
a1-an+1>an-an+1>0
1/(an-an+1)>1/(a1-an+1)
所以 1/(a1-a2)+1/(a2-a3)+...+1/(an-an+1)>1/(an-an+1)>1/(a1-an+1)
所以
1/(a1-a2)+1/(a2-a3)+...+1/(an-an+1)+1/(an+1-a1)>0