功率 P甲=I^2*R1=[V/(R1+R2)]^2*R1P乙=V^2/ R1P甲/P乙=4:9[V/(R1+R2)]^2*R1/(V^2/ R1)=4/9化简 R1^2/(R1+R2)^2=4/9两边开平方R1/(R1+r2)=2/33R1=2R1+2R2R1=2R2R1/R2=2/1R1:R2=2:1