Nesbitt’s Inequality

The Nesbitt’s inequality goes like this:

Screen Shot 2014-06-09 at 10.56.49 AM

I want to prove this in this post:

We define x to be a+b, y to be b+c and z to be a+c.

Screen Shot 2014-06-09 at 11.08.17 AM

Now we have to prove, that x/y+y/x is bigger or equal to 2. We multiply the equation with x times y times 2. We get: x^2+y^2 is bigger or equal to 2xy. Now we subtract 2xy on both sides and we get (x-y)^2 is bigger or equal to 0. This is true. Therefor we proved that x/y+y/x is bigger or equal to 2.

Now we have:

Screen Shot 2014-06-09 at 11.13.57 AM

This completes the proof.

 

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