Chapter 4.2 Graphs of Quadratics in Vertex or Intercept Form

Chapter 4.2Graphs of Quadratics

in Vertex or Intercept Form

Quadratic FunctionsQuadratic Functions all contain an x² term

Parent Function2y x

Axis of Symmetry – Divides the graph into mirror images

Vertex – Lowest or highest point on the graph

Vertex Form Vocab

• h is the horizontal shift

• k is the vertical shift

• a determines up/down orientation and fat/skinny parabolas.

• Vertex is at the point (h,k)

2y a x h k

Graph:

1. Identify a, h & k

2. Plot vertex & line of symmetry

3. Pick a value to the left of your x valuePlot point & Reflect across axis of symm.

4. Sketch curve.

22 3 2y x

2a 3h 2k 3,2Vertex 3Axis of Symm x

2x 0y

geogebra

4.2 hk

Steps for ploting



3. Pick a x value to the left of your vertex and Plot the point.

4. Reflect across axis of symm.

5. Sketch curve.

Y

X

23 3 2y x




4. Sketch curve.

Y

X

22 4y x




4. Sketch curve.

Intercept Form

• x-intercepts are at (p,0) & (q,0)

• Axis of symmetry is halfway between p&q.

• a determines up/down orientation and fat/skinny parabolas.

y a x p x q

2

p qx

geogebra

4.2 pq

Graph:

1. Identify & plot the intercepts.

2. Find the axis of plug in and find y then. Plot the vertex.

3. Sketch the graph

2 2 2y x x 2,0 2,0

2

p qx

2 2

2

0x

2 0 2 0 2y 2 2 2 8

0, 8

Y

X

2 5 3y x x



3. Sketch the graph

Y

X

27 4

3y x x



3. Sketch the graph

Graph1.

2.

3.

4.

5.

6.

7.

22 8 7x x y

Y

X

Y

X

213 2

3y x 1. Identify a, h & k



4. Sketch curve.

Y

X

Questions?

Assignment

• p2493-11, 13-21, just graph, don’t follow the directions

Documents

Chapter 4.2 Graphs of Quadratics in Vertex or Intercept Form