已知数列lga,lgb,lgc与lga-lg2b,lg2b-lg3c,lg3c-lga都是等差数列.求证:b+c-a/a,a+c-b/b,2a+b-c/a也是等差
问题描述:
已知数列lga,lgb,lgc与lga-lg2b,lg2b-lg3c,lg3c-lga都是等差数列.求证:b+c-a/a,a+c-b/b,2a+b-c/a也是等差
答
先化简么,lga,lgb,lgc与lga-lg2b,lg2b-lg3c,lg3c-lga
接着,带入b+c-a/a,a+c-b/b,2a+b-c/a,
可得他们是相同的