我知道很简单,但我做不出来-_-///1、已知等差数列{An}的公差d≠0,且A1、A3、A9成等比数列,则(A1+A3+A9)/(A2+A4+A10)=?2、一个等比数列{An}共有2n+1项,奇数项之积为100,偶数项之积为120,则A n+1=?
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![我知道很简单,但我做不出来-_-///1、已知等差数列{An}的公差d≠0,且A1、A3、A9成等比数列,则(A1+A3+A9)/(A2+A4+A10)=?2、一个等比数列{An}共有2n+1项,奇数项之积为100,偶数项之积为120,则A n+1=?](/uploads/image/z/1675149-69-9.jpg?t=%E6%88%91%E7%9F%A5%E9%81%93%E5%BE%88%E7%AE%80%E5%8D%95%2C%E4%BD%86%E6%88%91%E5%81%9A%E4%B8%8D%E5%87%BA%E6%9D%A5-_-%2F%2F%2F1%E3%80%81%E5%B7%B2%E7%9F%A5%E7%AD%89%E5%B7%AE%E6%95%B0%E5%88%97%7BAn%7D%E7%9A%84%E5%85%AC%E5%B7%AEd%E2%89%A00%2C%E4%B8%94A1%E3%80%81A3%E3%80%81A9%E6%88%90%E7%AD%89%E6%AF%94%E6%95%B0%E5%88%97%2C%E5%88%99%EF%BC%88A1%2BA3%2BA9%29%2F%28A2%2BA4%2BA10%29%3D%3F2%E3%80%81%E4%B8%80%E4%B8%AA%E7%AD%89%E6%AF%94%E6%95%B0%E5%88%97%7BAn%7D%E5%85%B1%E6%9C%892n%2B1%E9%A1%B9%2C%E5%A5%87%E6%95%B0%E9%A1%B9%E4%B9%8B%E7%A7%AF%E4%B8%BA100%2C%E5%81%B6%E6%95%B0%E9%A1%B9%E4%B9%8B%E7%A7%AF%E4%B8%BA120%2C%E5%88%99A+n%2B1%3D%3F)
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