SOLUTION: if in ABC triangle ∠C=60∘ then prove that 1/(a+c)+1/(b+c)=3/(a+b+c)

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Question 1005149: if in ABC triangle ∠C=60∘ then prove that 1/(a+c)+1/(b+c)=3/(a+b+c)
Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
Multiply both sides by (a+c)(b+c)(a+b+c) to clear out the fractions and make life easier. That is, statement holds if and only if



With some simplification, this is equivalent to



or



However this statement is true by applying the law of cosines on triangle ABC, as angle C = 60 degrees.