1R=1R1+1R2+...1R=1R1+1R2+...

Question

R=ρ⋅lAR=ρ⋅lA

Answer 1

first, learn how to type fractions. For resistances in parallel,
1/R = 1/R1 + 1/R2 + ...

and why do you write everything twice?

and why is there no question?

Bogus post in so many ways ...