Hi you all

I have a quick and properly really easy question.

I saw around the internet that the minimum function can be written out:

$\displaystyle min\left\{ a,b\right\} =\frac{1}{2}\cdot(a+b-|a-b|)$

I haven't ever seen that before, so i am interested in knowing when it works and when it doesn't (and to some extent why it's true). I need to differentiate a minimum function in my exam in microeconomics so it would be a great help!

Best regards.