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Example Questions
Example Question #51 : Graphs
Find the center and the vertices of the following hyperbola:
In order to find the center and the vertices of the hyperbola given in the problem, we must examine the standard form of a hyperbola:
The point (h,k) gives the center of the hyperbola. We can see that the equation in this problem resembles the second option for standard form above, so right away we can see the center is at:
In the first option, where the x term is in front of the y term, the hyperbola opens left and right. In the second option, where the y term is in front of the x term, the hyperbola opens up and down. In either case, the distance tells how far above and below or to the left and right of the center the vertices of the hyperbola are. Our equation is in the first form, where the x term is first, so the hyperbola opens left and right, which means the vertices are a distance to the left and right of the center. We can now calculate by identifying it in our equation, and then go 3 units to the left and right of our center to find the following vertices:
Example Question #2 : Hyperbolas
Find the equations of the asymptotes for the hyperbola with the following equation:
For a hyperbola with its foci on the -axis, like the one given in the equation, recall the standard form of the equation:
, where is the center of the hyperbola.
Start by putting the given equation into the standard form of the equation of a hyperbola.
Group the terms together and terms together.
Factor out from the terms and from the terms.
Complete the squares. Remember to add the amount amount to both sides of the equation!
Add to both sides of the equation:
Divide both sides by .
Factor the two terms to get the standard form of the equation of a hyperbola.
The slopes of this hyperbola are given by the following:
For the hyperbola in question, and .
Thus, the slopes for its asymptotes are .
Now, plug in the center of the hyperbola, into the point-slope form of the equation of a line to get the equations of the asymptotes.
For the first equation,
For the second equation,
Example Question #5 : Hyperbolas
Which of the following correctly describes the hyperbola of the equation
.
A vertical hyperbola with center at .
A horizontal hyperbola with center at .
A horizontal hyperbola with center at .
A vertical hyperbola with center at .
A horizontal hyperbola with center at .
is the standard form of a horizontal hyperbola with center . Set ; this hyperbola has its center at .
Example Question #1 : Transformations
Which of the following represents a vertical shift up 5 units of f(x)?
Which of the following represents a vertical shift up 5 units of f(x)?
A vertical translation can be accomplished by adding the desired amount onto the end of the equation. This means that f(x)+5 will shift f(x) up 5 units.
Example Question #2 : Transformations
Which of the following represents a horizontal transformation of v(t) 3 units to the right?
Which of the following represents a horizontal transformation of v(t) 3 units to the right?
To perform a horizontal transformation on a function, we need to add or subtract a value within the function, which looks something like this:
Now, counter intuitively, when we shift right, we will subtract. If we wanted to shift left, we would add.
So, to shift 3 to the right, we need:
Example Question #3 : Transformations
The graph of a function is shown below, select the graph of
.
There are four fundamental transformations that allows us to think of a function as a transformation of a function ,
In our case, and , so the width and/or height of our function will not change in the coordinate plane.
We have and . The number will shift the function up units along the -axis on the coordinate plane. The number will shift unit to the right on the coordinate plane.
Example Question #3 : Transformations
Which of these parabolas has its vertex at (5,1)?
None of the other answers.
The correct answer is . Inside the portion being squared the distance moved is opposite the sign and is horizontal. Outside the squared portion the distance moved follows the sign (plus is up and minus is down) and is vertical.
For example the incorrect answer would have its vertex at (1,-5).
Example Question #4 : Transformations
What is the expression for this polynomial:
after being shifted to the right by 2?
To shift a polynomial to the right by 2, we must replace x with x-2 in whatever the expression for the polynomial is. The logic of this is that every x value has a y value associated with it, and we want to give every x value the y value associated with the point that is 2 before it.
So, to get our shifted polynomial, we plug in x-2 as noted.
and then we combine like terms:
Example Question #6 : Transformations
Consider an exponential function . If we want to reflect this function across the y-axis, which of the following equations would result in the desired reflection?
As a general rule, if you have a function , then in order to reflect across the x-axis, we compute , and in order to reflect across the y-axis, we compute . In our case, we are asked to compute the latter.
So, if , then .
Example Question #5 : Transformations
If we want a function to be reflected about the origin, what would the corresponding equation look like?
To compute a reflection about the x-axis, calculate , and to calculate a reflection about the y-axis, calculate . To compute a reflection about the origin, simply combine both reflections into .
In our case, .
So,
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