<p>The slope of the tangent at the point of inflection of \(y = x^3 - 3x^2 + 6x + 2009\) is equal to:</p>
Step-by-Step Solution
Key Concept: A point of inflection occurs where the second derivative equals zero and changes sign. The slope at any point on the curve is given by the first derivative dy/dx at that point.
Given the function $y = x^3 - 3x^2 + 6x + 2009$.
**Step 1: Find the first derivative.**
The first derivative of the function is:
$$ \frac{dy}{dx} = 3x^2 - 6x + 6 $$
**Step 2: Find the second derivative.**
The second derivative of the function is:
$$ \frac{d^2y}{dx^2} = 6x - 6 $$
**Step 3: Determine the potential point of inflection.**
A point of inflection occurs where the second derivative is equal to zero. Setting the second derivative to zero:
$$ 6x - 6 = 0 $$
$$ 6x = 6 $$
$$ x = 1 $$
**Step 4: Verify the point of inflection.**
To confirm that $x=1$ is a point of inflection, we examine the sign of the second derivative around $x=1$.
For $x < 1$, $\frac{d^2y}{dx^2} = 6x - 6 < 0$, indicating the function is concave down.
For $x > 1$, $\frac{d^2y}{dx^2} = 6x - 6 > 0$, indicating the function is concave up.
Since the concavity changes at $x=1$, it is a point of inflection.
**Step 5: Calculate the slope of the tangent at the point of inflection.**
The slope of the tangent at the point of inflection is the value of the first derivative evaluated at $x=1$.
$$ \text{Slope} = \left.\frac{dy}{dx}\right|_{x=1} = 3(1)^2 - 6(1) + 6 $$
$$ \text{Slope} = 3 - 6 + 6 $$
$$ \text{Slope} = 3 $$
Correct Answer: a