已知一节点所带负荷，有功功率为P，视在功率为S，则功率因数角φ为(    )

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69497' and id < 4501891 and id<>'4501891' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69497' and id > 4501891 and id<>'4501891' order by id asc limit 5