仅供参考
解答如下图片
设bn=根号an 移项
a1=8, a2=18
√a(n+2) +√an = 2√a(n+1)
√a(n+2) -√a(n+1) = √a(n+1) - √an
=> {√a(n+1) - √an } 是等比数列, q=1
√a(n+1) - √an = √a2 -√a1
=3√2 -2√2
√a(n+1) - √an = √2
√an - √a1 = √2(n-1)
√an - 2√2 = √2(n-1)
√an =√2(n+1)
an =2(n+1)^2
内容全部来源于网络收集，如有侵权，请联系网站删除：QQ：24596024