如图所示：若改变R，则可获得最大功率，最大功率是（   ）。

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69307' and id < 4487239 and id<>'4487239' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69307' and id > 4487239 and id<>'4487239' order by id asc limit 5