Proving 3/4 is Infimum of A: A = { x^2 +x + 1 }

[mercuryman]

Homework Statement

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

Homework Equations

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

The Attempt at a Solution

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

 

[mfb]

I've assumed there is a M<3/4 that x^2 +x + 1>M

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.

 

[HallsofIvy]

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