已知锐角△ABC的内角A，B，C的对边分别为a，b，c，23cos2A+cos2A=0，a=7，c=6，则b=（  ）

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku_ where sourceid='23672' and id < 2058647 and id<>'2058647' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='23672' and id > 2058647 and id<>'2058647' order by id asc limit 5