√2,3-√2,2,3,4+√2,( )A.5+2√2 B.6+5√2 C.7+3√2 D.9+6√2

作者: tihaiku 人气: - 评论: 0
问题 √2,3-√2,2,3,4+√2,( )
选项 A.5+2√2 B.6+5√2 C.7+3√2 D.9+6√2
答案 C
解析 数列无明显特征,优先考虑做差。做差后得到新数列:3-2√2,√2-1,1,√2+1,()。递推可得:(3-2√2)+2×(√2-1)=1,(√2-1)+2×1=√2+1,即新数列第一项+第二项的2倍=第三项,故新数列的下一项=1+2×(√2+1)=2√2+3,由此可得所求项=(4+√2)+(2√2+3)=3√2+7。 故正确答案为C。

猜你喜欢

更多 网友评论0 条评论)
暂无评论
错误啦!

错误信息

  • 消息: [程序异常] : MISCONF Redis is configured to save RDB snapshots, but it's currently unable to persist to disk. Commands that may modify the data set are disabled, because this instance is configured to report errors during writes if RDB snapshotting fails (stop-writes-on-bgsave-error option). Please check the Redis logs for details about the RDB error.
  • 文件: /twcms/kongphp/cache/cache_redis.class.php
  • 位置: 第 85 行
    <?php echo 'KongPHP, Road to Jane.'; ?>