设Um是交流电压最大值，Im是交流电流最大值，则视在功率S等于（   ）。

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69471' and id < 4499918 and id<>'4499918' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69471' and id > 4499918 and id<>'4499918' order by id asc limit 5