McGraw Hill Integrated II, 2012
MH
McGraw Hill Integrated II, 2012 View details
Mid-Chapter Quiz
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Exercise 20 Page 132

Start with a reflection across the x-axis.

Transformations: Reflection across the x-axis, and translation one unit up
Graph:

We want to describe how to transform the parent function f(x)=x^2 to the graph of the given quadratic function. g(x)=-x^2+1 To do so, we need to consider four possible transformations.

  1. Reflections
  2. Stretches and compressions
  3. Horizontal translations
  4. Vertical translations

    Notice that we only need to consider the first and the fourth transformation.

    Reflection

    Whenever x^2 is multiplied by a negative number, we will start by reflecting the graph across the x-axis.

    Note how each x-coordinate stays the same and how each y-coordinate changes its sign.

    Vertical Translation

    If an addition or subtraction is applied to the whole function, the graph will be vertically translated. In the case of addition, the graph will be translated up. In the case of subtraction, it will be moved downwards. In the given equation, 1 is added to the whole function, so the previous graph will be translated one unit up.

    Final Graph

    Let's now graph the given function and the parent function f(x)=x^2 on the same coordinate grid.

    Finally, let's summarize how to draw the graph of the given function when starting with the parent function, f(x)=x^2.

    • Reflection across the x-axis
    • Translation one unit up