Question

Derive an expression for equivalent resistance 'R' when R1,R2,R3 are connect in series as parallel?

Answer 1

when connected in parallel:
1/R1 +1/R2 +1/R3=1/R

when connected in series:
R1+R2+R3=R

Answer 2

 1/R(p)= 1/R1 + 1/R2 + 1/R3