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Example Questions
Example Question #263 : Coordinate Geometry
Below is the graph of the function :
Which of the following could be the equation for ?
First, because the graph consists of pieces that are straight lines, the function must include an absolute value, whose functions usually have a distinctive "V" shape. Thus, we can eliminate f(x) = x2 – 4x + 3 from our choices. Furthermore, functions with x2 terms are curved parabolas, and do not have straight line segments. This means that f(x) = |x2 – 4x| – 3 is not the correct choice.
Next, let's examine f(x) = |2x – 6|. Because this function consists of an abolute value by itself, its graph will not have any negative values. An absolute value by itself will only yield non-negative numbers. Therefore, because the graph dips below the x-axis (which means f(x) has negative values), f(x) = |2x – 6| cannot be the correct answer.
Next, we can analyze f(x) = |x – 1| – 2. Let's allow x to equal 1 and see what value we would obtain from f(1).
f(1) = | 1 – 1 | – 2 = 0 – 2 = –2
However, the graph above shows that f(1) = –4. As a result, f(x) = |x – 1| – 2 cannot be the correct equation for the function.
By process of elimination, the answer must be f(x) = |2x – 2| – 4. We can verify this by plugging in several values of x into this equation. For example f(1) = |2 – 2| – 4 = –4, which corresponds to the point (1, –4) on the graph above. Likewise, if we plug 3 or –1 into the equation f(x) = |2x – 2| – 4, we obtain zero, meaning that the graph should cross the x-axis at 3 and –1. According to the graph above, this is exactly what happens.
The answer is f(x) = |2x – 2| – 4.
Example Question #261 : Coordinate Geometry
Which of the following could be a value of for
?
The graph is a down-opening parabola with a maximum of . Therefore, there are no y values greater than this for this function.
Example Question #5 : How To Graph A Function
What is the equation for the line pictured above?
A line has the equation
where
is the
intercept and
is the slope.
The intercept can be found by noting the point where the line and the y-axis cross, in this case, at
so
.
The slope can be found by selecting two points, for example, the y-intercept and the next point over that crosses an even point, for example, .
Now applying the slope formula,
which yields .
Therefore the equation of the line becomes:
Example Question #264 : Coordinate Geometry
Which of the following graphs represents the y-intercept of this function?
Graphically, the y-intercept is the point at which the graph touches the y-axis. Algebraically, it is the value of when
.
Here, we are given the function . In order to calculate the y-intercept, set
equal to zero and solve for
.
So the y-intercept is at .
Example Question #265 : Coordinate Geometry
Which of the following graphs represents the x-intercept of this function?
Graphically, the x-intercept is the point at which the graph touches the x-axis. Algebraically, it is the value of for which
.
Here, we are given the function . In order to calculate the x-intercept, set
equal to zero and solve for
.
So the x-intercept is at .
Example Question #266 : Coordinate Geometry
Which of the following represents ?
A line is defined by any two points on the line. It is frequently simplest to calculate two points by substituting zero for x and solving for y, and by substituting zero for y and solving for x.
Let . Then
So our first set of points (which is also the y-intercept) is
Let . Then
So our second set of points (which is also the x-intercept) is .
Example Question #1 : Graphing
Suppose .
To obtain the graph of , shift the graph
a distance of
units .
Up and right
To the left
Upwards
To the right
Downwards
Upwards
There are four shifts of the graph y = f(x):
y = f(x) + c shifts the graph c units upwards.
y = f(x) – c shifts the graph c units downwards.
y = f(x + c) shifts the graph c units to the left.
y = f(x – c) shifts the graph c units to the right.
Example Question #841 : Act Math
Which of the following graphs does NOT represent a function?
All of the graphs are functions.
This question relies on both the vertical-line test and the definition of a function. We need to use the vertical-line test to determine which of the graphs is not a function (i.e. the graph that has more than one output for a given input). The vertical-line test states that a graph represents a function when a vertical line can be drawn at every point in the graph and only intersect it at one point; thus, if a vertical line is drawn in a graph and it intersects that graph at more than one point, then the graph is not a function. The circle is the only answer choice that fails the vertical-line test, and so it is not a function.
Example Question #842 : Act Math
How would you plot the point ?
From the origin, go right units, and up
units
From the origin, go up units, and right
units
From the origin, go right units, and down
units
From the origin, go left units, and up
units
From the origin, go right units, and up
units
For the ordered pair
The first number is for the x-axis, so because it is positive you go right .
The second number is for the y-axis, so because it is positive you go up .
Example Question #843 : Act Math
How would you plot the point ?
From the origin, go right units, and down
units
From the origin, go right units, and up
units
From the origin, go left units, and up
units
From the origin, go left units, and down
units
From the origin, go left units, and up
units
For the ordered pair we would do the following.
The first number is for the x-axis, so because it is negative you go left units.
The second number is for the y-axis, so because it is positive you go up units.
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