DECK 2: QUADRATIC TERMS INTRO Flashcards
What is the shape of a quadratic graph called?
A parabola
What is the highest or lowest point (x,y) called on a parabola? It is on the AOS. It is sometimes written as (h,k)
The vertex.
Is the vertex of a parabola always on the axis of symmetry?
YES. The x value of the vertex is the axis of symmetry.
What is the axis of symmetry?
It is the vertical line that goes through the middle of the parabola- parabola folds on itself. THE VERTEX IS ON IT
What does VERTICAL mean?
Up and Down
What does the line x = 10 look like?
A vertical line through 10 on the x axis
What is the equation of a vertical line through 7 on the x axis? (visualize a vertical line through 7 on the x axis)
x = 7
All vertical lines have equation
“ X = some number”
Since the axis of symmetry is a vertical line, the equation of the axis of symmetry is always:
X = some number
you have to write “x = ? “
What does HORIZONTAL mean?
Left and right
Do all parabolas have x-intercepts? If so, how many?
NO - they may have
NONE, ONE or TWO.
Do all parabolas have y-intercepts? If so, how many?
YES, they all have EXACTLY ONE y intercept.
How can a parabola have no real roots (no x intercepts)?
If it doesn’t touch the x axis. Smiling parabola above, or frowning parabola below.
How can a parabola have only one real root (one x intercept)
If it touches the x-axis only at one point (the vertex) and “bounces off”
How can a parabola have two real roots (two x intercepts)
If it crosses twice.
How do you find the y intercept for any linear or quadratic function?
Set X=0 and solve for y
How do you find the x-intercepts of any linear or quadratic functions?
Set Y=0 and solve for x (this involves setting each factor = 0 and solving for x for each)
What are the three forms of quadratic functions?
standard, vertex and factored (intercept) forms
What form?
f(x)=ax 2 +bx+c
Standard
What is the standard form of a quadratic?
f(x)=ax 2 +bx+c
What form?
f(x) = a(x-h) 2 +k
Vertex form
What is the vertex form of a quadratic?
f(x) = a(x-h) 2 +k
What form?
f(x)=a(x-Z)(x-Z)
Intercept or Factored form
What is the intercept (factored) form of a quadratic?
f(x)=a(x-Z)(x-Z) where Z and Z are ZEROS, roots, x-intercepts
For any polynomial in factored form, how do you find the ROOTS, ZEROS, SOLUTIONS, X-INTERCEPTS?
SET THE FACTORS EQUAL TO ZERO AND SOLVE!
EX: f(x)=3 (x-5)(x+10) Roots are 5 and -10
because (x-5)=0 when x=5
and (x+10)=0 wnen x=-10
You can often do the math in your head. But if a factor is (3x-5), you would have to solve for
x in 3x-5=0