1. The problem asks us to find the greatest value of the expression $$\frac{1}{4x^2 - 4x + 7}$$ and the value of $x$ at which this maximum occurs.
2. From part (a), we have rewritten the quadratic expression in the denominator as $$4x^2 - 4x + 7 = 4(x - \frac{1}{2})^2 + 6$$ where $p=4$, $q=-\frac{1}{2}$, and $r=6$.
3. Since the denominator is $4(x - \frac{1}{2})^2 + 6$, and squares are always non-negative, the smallest value of the denominator occurs when the squared term is zero, i.e., when $$x - \frac{1}{2} = 0 \implies x = \frac{1}{2}$$.
4. At this $x$ value, the denominator is minimized to $$4 \times 0^2 + 6 = 6$$.
5. Because the expression is $$\frac{1}{\text{denominator}}$$, the greatest value of the whole expression occurs when the denominator is smallest.
6. Therefore, the greatest value is $$\frac{1}{6}$$, and it occurs at $$x = \frac{1}{2}$$.
7. We assume the minimum of the denominator because the reciprocal function $$f(y) = \frac{1}{y}$$ is decreasing for positive $y$, so minimizing the denominator maximizes the fraction.
This explains why we find the minimum of the quadratic in the denominator to get the maximum of the reciprocal function.
Max Value Reciprocal 220Ba5
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