quadratics functions polynomials Flashcards
How do you find the x-intercepts?
Plug y as zero
How do you find the axis of symmetry?
The axis of symmetry is in between the x-intercepts.
Add the two x-intercepts and divide by two.
Can also be found by -b/2a
How do you find the coordinates of the vertex?
Method One: use the axis of symmetry as a point for x and plug in for y
a > 0
^_^ concave up
the graph cuts the x-axis twice when
discriminant greater than zero
the graph touches the x-axis if
discriminant is equal to zero
the graph misses the x-axis when
discriminant is less than zero
Definition of quadratic function
A quadratic function is a relationship between two variables x and y which can be written in the form
y=ax^2+bx+c
Where aa, bc, constants, a is not zero
a < 0
concave down
if -1 < a <1
a is not zero
the graph is wider than y = x^2
if a < -1 or a > 1
the graph is narrower than
y = x^2
general form
y = ax^2 + bx + c
completed square form
y = a (x-h)^2 + k
where is the vertex in completed square form?
h, k
What is the discriminant
-b^2 - 4(ac)