Question

Difficulty: EasyStationary Points, Maxima, and Minima

What is the xx-coordinate of the stationary point of the curve y=3x212x+7y = 3x^2 - 12x + 7?

  1. 22Answer
  2. B
    2-2
  3. C
    44
  4. D
    77

Answer

The xx-coordinate of the stationary point is 22.
To find the stationary point, take the derivative of y=3x212x+7y = 3x^2 - 12x + 7 with respect to xx, obtaining dydx=6x12\frac{dy}{dx} = 6x - 12. Setting the derivative equal to zero gives 6x12=06x - 12 = 0, which solves to x=2x = 2.

Step-by-Step Solution

1
Differentiate the equation of the curve with respect to xx
dydx=6x12\frac{dy}{dx} = 6x - 12
Stationary points occur where the first derivative (gradient) of the function is equal to zero.
2
Set the derivative to zero and solve for xx
6x - 12 = 0 \implies 6x = 12 \implies x = 2
Solving this linear equation gives the exact value of xx at which the tangent to the curve is horizontal.

Key Concept

Stationary Points of a Curve
Estimated Time:45s
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