Question 3
For real numbers $a,b,c$, find the minimum of $F(a,b,c)=(a+b)^4+(b+c)^4+(c+a)^4-\tfrac47(a^4+b^4+c^4)$.
The supplied source has no question point values. Each problem uses 1 editorial point for import compatibility; this is not an official scoring scale.
The supplied source has no question point values. Each problem uses 1 editorial point for import compatibility; this is not an official scoring scale.