Question

两个电阻R1、R2并联的总电阻为R12=R1R2/R1+R2+R3,但是这个是想法是错误的。，

请运用所用的电学知识加以证明

Answer 1

两个电阻R1、R2并联的总电阻为R1R2/(R1+R2)
然而R1R2/R1+R2+R3=(R1R2+R1R2+R1R3)/R1=2R2+R3
显然R1R2/(R1+R2)=/=2R2+R3

Answer 2

证明不了，两个电阻R1、R2并联的总电阻为R并=R1R2/（R1+R2）可证明；
1／R并＝1／R1＋1／R2＝R2／R1R2＋R1／R1R2＝（R2＋R1）／R1R2
1／R并＝（R2＋R1）／R1R2
即R并＝R1R2／（R2＋R1）

Answer 3

你这个问题不对吧？怎么有个R3
两个电阻R1、R2并联的总电阻为R1R2/(R1+R2)
然而R1R2/R1+R2+R3=(R1R2+R1R2+R1R3)/R1=2R2+R3
显然R1R2/(R1+R2)=/=2R2+R3