Question

find the equivalent resistance

Answer 1

I know that finding the equivalent resistance depend on whether resistors are in serie (R1+R2+...+Rn) or parallel (1/Req=1/R1+1/R2+...+1/Rn), but i don't know how to apply that to find the equivalent resistance of this circuit (not including Ra):



simulate this circuit – Schematic created using CircuitLab

My solution:



simulate this circuit

R3, R1 and R2 are in parallel so: 1/Req=1/R3+1/R1+1/R2 so Req=3.299 Ohm.

I assumed that R3 isn't in parallel with R2 and R1, so I calculated Req in different ways: Req=(R1//R2)+R3+ Or: Req=(R1//R3)+R2 Or: Req=(R3//R2)+R1