已知数列an的前n项和为sn若sn=3an+2n证明数列an-2是等比数列
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/02 01:20:05
![已知数列an的前n项和为sn若sn=3an+2n证明数列an-2是等比数列](/uploads/image/f/45467-35-7.jpg?t=%E5%B7%B2%E7%9F%A5%E6%95%B0%E5%88%97an%E7%9A%84%E5%89%8Dn%E9%A1%B9%E5%92%8C%E4%B8%BAsn%E8%8B%A5sn%3D3an%2B2n%E8%AF%81%E6%98%8E%E6%95%B0%E5%88%97an-2%E6%98%AF%E7%AD%89%E6%AF%94%E6%95%B0%E5%88%97)
Warning: PDO::query(): MySQL server has gone away in /mnt/www/zhanqunzuoye/library/mysql/pdo_mysql.php on line 60
Warning: PDO::query(): Error reading result set's header in /mnt/www/zhanqunzuoye/library/mysql/pdo_mysql.php on line 60
Fatal error: Uncaught Error: Call to undefined method pdo_mysql::sqlError() in /mnt/www/zhanqunzuoye/library/mysql/pdo_mysql.php:106 Stack trace: #0 /mnt/www/zhanqunzuoye/library/mysql/pdo_mysql.php(61): pdo_mysql->getPDOError('select id,title...') #1 /mnt/www/zhanqunzuoye/library/mysql/pdo_mysql.php(80): pdo_mysql->_fetch('select id,title...', 1) #2 /mnt/www/zhanqunzuoye/library/mysql/pdo_mysql.php(179): pdo_mysql->getAll('select id,title...') #3 /mnt/www/zhanqunzuoye/library/mysql/mtable.php(88): pdo_mysql->getAllPdo('select id,title...', NULL) #4 /mnt/www/zhanqunzuoye/control/public/indexControl.php(40): mtable->getAll('select id,title...') #5 /mnt/www/zhanqunzuoye/library/core/core.php(84): indexControl->sorandAction() #6 /mnt/www/zhanqunzuoye/library/core/control.php(45): core::gotoAction(Array) #7 /mnt/www/zhanqunzuoye/view/public/focus/show.php(15): control->action('sorand', 'index') #8 /mnt/www/zhanqunzuoye/library/core/control.php(24): require('/mnt/www/zhanqu...') #9 /mnt/www/zhanqunzuoye/control/public/focusCon in /mnt/www/zhanqunzuoye/library/mysql/pdo_mysql.php on line 106