不等式 对一切 R恒成立，则实数 a的取值范围是(  )

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='15529' and id < 2638480 and id<>'2638480' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='15529' and id > 2638480 and id<>'2638480' order by id asc limit 5