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Example Questions
Example Question #1 : How To Graph A Quadratic Function
has as its graph a vertical parabola on the coordinate plane. You are given that
and
, but you are not given
.
Which of the following can you determine without knowing the value of ?
I) Whether the graph is concave upward or concave downward
II) The location of the vertex
III) The location of the -intercept
IV) The locations of the -intercepts, if there are any
V) The equation of the line of symmetry
III and IV only
I and V only
I and III only
I, II, and V only
I, III, and IV only
I and III only
I) The orientation of the parabola is determined solely by the sign of . Since
, the parabola can be determined to be concave downward.
II and V) The -coordinate of the vertex is
; since you are not given
, you cannot find this. Also, since the line of symmetry has equation
, for the same reason, you cannot find this either.
III) The -intercept is the point at which
; by substitution, it can be found to be at
.
known to be equal to 9, so the
-intercept can be determined to be
.
IV) The -intercept(s), if any, are the point(s) at which
. This is solvable using the quadratic formula
Since all three of and
must be known for this to be evaluated, and only
is known, the
-intercept(s) cannot be identified.
The correct response is I and III only.
Example Question #2 : How To Graph A Quadratic Function
Which of the following equations can be graphed with a vertical parabola with exactly one -intercept?
The graph of has exactly one
-intercept if and only if
has exactly one solution - or equivalently, if and only if
Since in all three equations, , we find the value of
that makes this statement true by substituting and solving:
The correct choice is .
Example Question #1001 : Problem Solving Questions
Give the vertex of the graph of the function
.
This can be answered rewriting this expression in the form
.
Once this is done, we can identify the vertex as the point .
The vertex is
Example Question #163 : Coordinate Geometry
has as its graph a vertical parabola on the coordinate plane. You are given that
and
, but you are not given the value of
.
Which of the following can you determine without knowing the value of ?
I) Whether the graph is concave upward or concave downward
II) The location of the vertex
III) The location of the -intercept
IV) The locations of the -intercepts, if there are any
V) The equation of the line of symmetry
I, III, and IV only
I, II, and V only
II and V only
III and IV only
I and V only
I and V only
I) The orientation of the parabola is determined solely by the sign of . Since
, a positive value, the parabola can be determined to be concave upward.
II) The -coordinate of the vertex is
; since you given both
and
, you can find this to be
The -coordinate is equal to
. However, you need the entire equation to determine this value; since you do not know
, you cannot find the
-coordinate. Therefore, you cannot find the vertex.
III) The -intercept is the point at which
; by substitution, it can be found to be at
.
is unknown, so the
-intercept cannot be found.
IV) The -intercept(s), if any, are the point(s) at which
. This is solvable using the quadratic formula
Since all three of and
must be known for this to be evaluated, and
is unknown, the
-intercept(s) cannot be identified.
V) The line of symmetry has equation . When exploring the vertex, we found that this value is equal to
, so the line of symmetry is the line of the equation
.
The correct response is I and V only.
Example Question #164 : Coordinate Geometry
has as its graph a vertical parabola on the coordinate plane. You are given that
, but you are given no other information about these values.
Which of the following can you determine without knowing the value of ?
I) Whether the graph is concave upward or concave downward
II) The location of the vertex
III) The location of the -intercept
IV) The locations of the -intercepts,or whether there are any
V) The equation of the line of symmetry
II, IV, and V only
I, IV, and V only
II and V only
I, II, IV, and V only
IV and V only
I, IV, and V only
I) The orientation of the parabola is determined solely by the sign of . It is given in the problem that
is negative, so it follows that the parabola is concave downward.
II) The -coordinate of the vertex is
; since
, this number is
. The
-coordinate is
, but since we do not know the values of
,
, and
, we cannot find this value. Therefore, we cannot know the vertex.
III) The -intercept is the point at which
; by substitution, it can be found to be at
.
is unknown, so the
-intercept cannot be found.
IV) The -intercept(s), if any, are the point(s) at which
. This is solvable using the quadratic formula
Since , this can be rewritten and simplified as follows:
However, since has no real square root,
has no real solutions, and its graph has no
-intercepts.
V) The line of symmetry has equation . When exploring the vertex, we found that this value is equal to
, so the line of symmetry is the line of the equation
.
The correct response is I, IV, and V only.
Example Question #62 : Coordinate Geometry
The graphs of the functions and
have the same pair of
-intercepts.
If we define , which of the following is a possible definition of
?
The -intercepts of the parabola
can be determined by setting and solving for
:
or
The intercepts of the parabola are
and
.
We can check each equation to see whether these two ordered pairs satisfy them.
:
Each of these equations has a parabola that does not have as an
-intercept. However, we look at
and
are also
-intercepts of the graph of this function, so this is the correct choice.
Example Question #151 : Advanced Geometry
A vertical parabola has two -intercepts, one at
and one at
.
Which of the following must be true about this parabola?
The parabola must have the line of the equation as its line of symmetry.
The parabola must have as its vertex.
None of the statements in the other choices must be true.
The parabola must be concave downward.
The parabola must have its -intercept at
.
The parabola must have the line of the equation as its line of symmetry.
A parabola with its -intercepts at
and at
has as its equation
for some nonzero . If this is multiplied out, the equation can be rewritten as
or, simplified,
The sign of quadratic coefficient determines whether it is concave upward or concave downward. We do not have the sign or any way of determining it.
The -coordinate of the
-intercept is the contant,
, but without knowing
, we have no way of knowing
.
The -coordinate of the vertex of
is the value
. since
, this expression becomes
The -coordinate is
,
but without knowing , this coordinate, and the vertex itself, cannot be determined.
The line of symmetry is the line ; this value was computed to be equal to 6, so the line can be determined to be
.
Example Question #1001 : Problem Solving Questions
Which of the following is the equation of the line of symmetry of a vertical parabola on the coordinate plane with its vertex at ?
The line of symmetry of a vertical parabola is a vertical line, the equation of which takes the form for some
. The line of symmetry passes through the vertex, which here is
, so the equation must be
.
Example Question #166 : Coordinate Geometry
Which of the following is the equation of the line of symmetry of a horizontal parabola on the coordinate plane with its vertex at ?
The line of symmetry of a horizontal parabola is a horizontal line, the equation of which takes the form for some
. The line of symmetry passes through the vertex, which here is
, so the equation must be
.
Example Question #21 : Graphing
The graphs of the functions and
have the same
-intercept.
If we define , which of the following is a possible definition of
?
The -coordinate of the
-intercept of the graph of a function of the form
- a quadratic function - is the point
. Since
, the
-intercept is at the point
.
Because of this, the graph of has its
-intercept at
. Among the other choices, only
has a graph with its
-intercept also at
.
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