The parabola y = x² is reflected across the x-axis and then scaled vertically by a factor of 5. What is the equation of the new parabola?

Respuesta :

Answer:

  y = -5x²

Step-by-step explanation:

You want the equation of the parabola y = x² after reflection over the x-axis and vertical scaling by a factor of 5.

Scale factor

A function f(x) that is vertically scaled by a factor of k will be k·f(x). When a vertical reflection is also involved, the sign of k will be negative.

Your reflected, scaled function will have k = -5:

  y = -5x²

Final answer:

The original parabola y = x², when reflected across the x-axis and scaled vertically by 5, results in the new equation y = -5x².

Explanation:

The original parabola is given by the equation y = x². When this parabola is reflected across the x-axis, the y-values change sign, hence the new equation will be y = -x².

Further, when this reflected parabola is scaled vertically by a factor of 5, each y-value is multiplied by 5. Therefore, the equation of the new parabola after scaling becomes y = -5x².

Reflection across the x-axis inverts the sign of the y-coordinates of the parabola. So, the parabola which opens upwards (y = x²) will now open downwards (y = -x²). The vertical scaling by a factor of 5 amplifies the stretch of the parabola, making it 'wider' by multiplying the y-values by 5.

  1. Reflect parabola across the x-axis: y = x² becomes y = -x²
  2. Scale vertically by a factor of 5: y = -x² becomes y = -5x²

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