SOLUTION: Find r if: 1/r=1/r1+1/r2

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Question 351557: Find r if:
1/r=1/r1+1/r2
Found 2 solutions by Fombitz, mananth:
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
1%2Fr=1%2Fr1%2B1%2Fr2
Multiply both sides by r%2Ar1%2Ar2, assuming r%3C%3E0,r1%3C%3E0,r2%3C%3E0
r1%2Ar2=r%2Ar2%2Br%2Ar1
r%28r1%2Br2%29=r1%2Ar2
highlight_green%28r=%28r1%2Ar2%29%2F%28r1%2Br2%29%29

Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
1/r=1/r1+1/r2
LCM of RHS r1r2
1/r= (r1+r2)/r1r2
take reciprocal
r= r1r2/(r1+r2)
....
m.ananth@hotmail.ca