等差数列求和 难题设{An}是等差数列,求证:以bn=a1+a2+...an/n (n属于N+)为通项公式的数列{bn}是等差数列
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![等差数列求和 难题设{An}是等差数列,求证:以bn=a1+a2+...an/n (n属于N+)为通项公式的数列{bn}是等差数列](/uploads/image/z/8576622-54-2.jpg?t=%E7%AD%89%E5%B7%AE%E6%95%B0%E5%88%97%E6%B1%82%E5%92%8C+%E9%9A%BE%E9%A2%98%E8%AE%BE%EF%BD%9BAn%7D%E6%98%AF%E7%AD%89%E5%B7%AE%E6%95%B0%E5%88%97%2C%E6%B1%82%E8%AF%81%EF%BC%9A%E4%BB%A5bn%3Da1%2Ba2%2B...an%2Fn+%28n%E5%B1%9E%E4%BA%8EN%2B%EF%BC%89%E4%B8%BA%E9%80%9A%E9%A1%B9%E5%85%AC%E5%BC%8F%E7%9A%84%E6%95%B0%E5%88%97%EF%BD%9Bbn%7D%E6%98%AF%E7%AD%89%E5%B7%AE%E6%95%B0%E5%88%97)
等差数列求和 难题设{An}是等差数列,求证:以bn=a1+a2+...an/n (n属于N+)为通项公式的数列{bn}是等差数列
等差数列求和 难题
设{An}是等差数列,求证:以bn=a1+a2+...an/n (n属于N+)为通项公式的数列{bn}是等差数列
等差数列求和 难题设{An}是等差数列,求证:以bn=a1+a2+...an/n (n属于N+)为通项公式的数列{bn}是等差数列
a(n)=a+(n-1)d,
b(n)=[a(1)+...+a(n)]/n = [na+n(n-1)d/2]/n = a+ (n-1)(d/2).
{b(n)}为首项为a(1)=a,公差为d/2的等差数列.