Unit Four Part I- Introduction to Quadratic Functions

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Unit Four

Part I

Key Concepts

-the relation

defined by y=ax2+bx+c is a

quadratic relation

- the graph of

a quadratic equation is called a parabola

- the vertex

of a parabola is either the minimum or the maximum point on the graph

-if a

relation is quadratic, the second differences are constant, but the first

differences are not.

y=

a(x-h)2+k

The value before “a” indicates the direction of opening

(positive-up)

This value indicates

the stretch/compress factor.

This value indicates the

horizontal shift, and is also half the coordinate of the vertex (positive-to

the left)

This value indicates

the vertical shift and is also half the coordinate of the vertex (positive-up).

- a relation of the form y= a(x-r)(x-s) is also quadratic.

- ‘r’ and ‘s’ are the zeroes/ x-intercepts of the parabolas.

- the x-coordinate of the vertex is on the axis of symmetry, which

passes through the midpoint of the line connecting the zeroes.

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