Question 85641
RT=1/[(1/R1)+(1/R2)]
Words: Total Resistance of two resistences (R1 and R2) = the inverse of the sum of the inverse of two resistences.

---------------
The common denominator of the denominator is R1R2
Then:
RT =1/{[R1+R2]/[R1R2]}
Invert to get:
RT = (R1R2]/[R1+R2]
================
Cheers,
Stan H.