Question

starting with the equation for resistors in parallel, prove that for two resistors R1 and R2, the equivalent total resistance (RT) is: Rt=R1R2/R1+R2

I kind of understand it, but it isn't giving me the right answer which should be the equation?

Answer 1

This is not physics, it is algebra I.

1/rt=1/r1+1/r2

common denominator on right is r1r2

1/rt=r1r2/r1r2 (1/r1+1/r2)
1/rt=(r2+r1)/r1r2
multiply both sides by rt*r1r2/(r1+r2)

r1r2/(r1+r2)=rt