In math 1 you worked with quadratic functions. Standard form of a quadratic is f(x) = ax ² + bx + c and its graph is called a parabola. In the image below you can see the key features of a quadratic function. In this section we will be reviewing how to find these parts given a graph and a function rule.
Vertex: The "turning point"of the parabola. This will be the maximum (if the parabola opens downward) or a minimum value (if the parabola opens upward).
x - intercepts/solutions/zeros/roots: The point(s) where the parabola crosses the x-axis (y = 0) y-intercept: The point where the parabola crosses the y-axis (x = 0). Axis of Symmetry: The imaginary line that goes through the vertex and cuts the parabola into 2 equal parts. |
Watch the video linked below before completing the three practice skills to review quadratic functions.
First you will review identifying the parts given a graph. Complete at least 4 questions from each skill liked below.
Finding the y-intercept, Vertex and Axis of Symmetry in Standard Form
Finding the y-intercept
Recall that the y-intercept is when x = 0. When x = 0 is substituted into any quadratic function only the c value will remain.
f(x) = ax²+ bx + c
f(0) = a(0)²+ b(0) + c *f(0) means to substitute x = 0*
f(0) = c
Therefore when identifying the y-intercept of a quadratic function written standard form, simply look for
the c (constant).
Recall that the y-intercept is when x = 0. When x = 0 is substituted into any quadratic function only the c value will remain.
f(x) = ax²+ bx + c
f(0) = a(0)²+ b(0) + c *f(0) means to substitute x = 0*
f(0) = c
Therefore when identifying the y-intercept of a quadratic function written standard form, simply look for
the c (constant).
Find axis of symmetry the vertex in standard form
Since the axis of symmetry is a vertical line, the equation of this line will be x = ___. The x value will be the x value of the vertex because the AOS cuts through the vertex. Because of this when finding the axis of symmetry you will also have the x-coordinate of the vertex. To the right is the rule for finding the AOS.
This is a Math 1 review, copy example then complete the review skill that is linked. If you need additional help watch the help video.
Since the axis of symmetry is a vertical line, the equation of this line will be x = ___. The x value will be the x value of the vertex because the AOS cuts through the vertex. Because of this when finding the axis of symmetry you will also have the x-coordinate of the vertex. To the right is the rule for finding the AOS.
This is a Math 1 review, copy example then complete the review skill that is linked. If you need additional help watch the help video.