# Infimum proof

1. Oct 30, 2012

### mercuryman

1. The problem statement, all variables and given/known data

Giva a formal proof that 3/4 is the infimum of the set : A = { x^2 +x + 1 }

2. Relevant equations
I need a clear way to prove it - to understand the contradiction.

3. The attempt at a solution
I've assumed there is a M<3/4 that x^2 +x + 1>M. where is the contradiction?

2. Oct 30, 2012

### Staff: Mentor

I think you mean $x^2 +x + 1\leq M$? Otherwise it would be a bit pointless.

You should have given $x \in R$ somewhere.

3. Oct 30, 2012

### HallsofIvy

Staff Emeritus
Why is this posted under "physics"? It is clearly a math problem- complete the square.