Question

Recall that we saw the rule that if \(f\) is a function with derivative \(f' (x)\) and \(f (x) \neq 0\) then

\(\left( \frac{1}{f} \right)' = \frac{- f' (x)}{\left[ f (x) \right]^2}\)

Consider \(g (x) = \frac{1}{x^2 + x + 1}\)

For what value of \(x\) is the tangent line horizontal?