Let’s solve this step by step.
We are given the vertex form of a quadratic function:
f(x) = a(x - h)² + k
This form tells us important things about the graph (a parabola):
- The
vertex is at the point
(h, k)
- The
axis of symmetry is the vertical line
x = h
- The value of
a tells us if the parabola opens up or down, and how wide or narrow it is
Now, look at each labeled part in the diagram:
---
Part “a” — This shows a parabola that opens upward and is narrower than the parent function.
In the vertex form,
a controls the width and direction.
- If |a| > 1 → parabola is narrower
- If 0 < |a| < 1 → parabola is wider
- If a > 0 → opens up
- If a < 0 → opens down
Since this graph opens up and is narrower than the parent function (which has a = 1), then
a must be greater than 1. For example, a = 2 or a = 3 would make it narrower.
But we don’t need to pick an exact number unless asked — just understand what “a” represents.
→ So,
“a” affects the width and direction of the parabola.
---
Part “h” — This graph is shifted left or right compared to the parent function.
In the formula: f(x) = a(x - h)² + k
The
h value shifts the graph horizontally.
- If h is positive → shift RIGHT
- If h is negative → shift LEFT
Looking at the graph labeled “h”, it looks like the vertex is moved to the right (say, x = 2). That means h = 2.
So,
“h” gives the x-coordinate of the vertex and shifts the graph left/right.
Axis of symmetry is x = h.
---
Part “k” — This graph is shifted up or down.
In the formula,
k is added at the end.
- If k is positive → shift UP
- If k is negative → shift DOWN
The graph labeled “k” looks like it’s shifted up (maybe y = 3). So k = 3.
→ So,
“k” gives the y-coordinate of the vertex and shifts the graph up/down.
---
Vertex and Axis of Symmetry
From the formula:
Vertex = (h, k)
Axis of Symmetry = x = h
So for any quadratic in vertex form, you can read these directly from the equation.
---
Parent Function
The parent function is f(x) = x². Its vertex is at (0, 0), and it opens upward with a = 1.
All other graphs are transformations of this one.
---
Now, let’s fill in the blanks based on understanding:
In the box labeled “Vertex: ___ , Axis of Symmetry: ___”
We’re not given specific numbers, but since this is connected to the general formula, we use variables:
→ Vertex:
(h, k)
→ Axis of Symmetry:
x = h
That’s the standard answer when working with the general vertex form.
---
Final Answer:
Vertex: (h, k)
Axis of Symmetry: x = h
Parent Tip: Review the logic above to help your child master the concept of transformations of quadratics worksheet.