RealiseNothing
what is that?It is Cowpea
Re: HSC 2014 4U Marathon
![](https://latex.codecogs.com/png.latex?\bg_white \sqrt{(a+b+c)(a+b-c)(a+c-b)(b+c-a)} \leq a^2 + b^2 + c^2)
Expanding the LHS basically gives the result.
![](https://latex.codecogs.com/png.latex?\bg_white (a+b+c)(a+b-c)(a+c-b)(b+c-a) = 2(a^2b^2+b^2c^2+c^2a^2) - (a^4+b^4+c^4))
![](https://latex.codecogs.com/png.latex?\bg_white \leq (a^2+b^2+c^2)^2)
The problem is essentially showing that:It hatttesss you!
![]()
Expanding the LHS basically gives the result.