分类：教育/科学-学习帮助
问题：已知a>2，求证loga(a
已知a>2，求证loga(a-1)*loga(a+1)<1
回答：a>2 ==> a-1>1 ==> loga(a-1)*loga(a+1) > 0
2*根号[loga(a-1)*loga(a+1)]
< loga(a-1) +loga(a+1) 
= loga(a^2 -1)
< loga(a^2) = 2
因此，loga(a-1)*loga(a+1)<1