Functions and Graphs
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Algebra 2 › Functions and Graphs
A circle is graphed by the equation What is the distance from the center of the circle to the point
on a standard coordinate plane?
Explanation
First determine the center of the circle. The "x-3" portion of the circle equation tells us that the x coordinate is equal to 3. The "y-3" portion of the circle equation tells us that the y coordinate is equal to 3 as well. Therefore, the center of the circle is at (3,3).
To find the distance between (3,3) and (0,0), it is necessary to use the Pythagorean Theorem
. Where "a" and "b" are equal to 3
(to visualize, you may draw the two points on a graph, and create a triangle. The line connecting the two points is the hypotenuse, aka "c." )
What is the center of the circular function ?
Explanation
Remember that the "shifts" involved with circular functions are sort of like those found in parabolas. When you shift a parabola left or right, you have to think "oppositely". A right shift requires you to subtract from the x-component, and a left one requires you to add. Hence, this circle has no horizontal shift, but does shift 6 upward for the vertical component.
You can also remember the general formula for a circle with center at and a radius of
.
Comparing this to the given equation, we can determine the center point.
The center point is at (0,6) and the circle has a radius of 5.
What is the center and radius of the following equation, respectively?
Explanation
The equation given represents a circle.
represents the center, and
is the radius.
The center is at:
Set up an equation to solve the radius.
The radius is:
The answer is:
Consider the following two functions:
and
How is the function shifted compared with
?
units left,
units down
units right,
units down
units left,
units up
units right,
units down
units left,
units down
Explanation
The portion results in the graph being shifted 3 units to the left, while the
results in the graph being shifted six units down. Vertical shifts are the same sign as the number outside the parentheses, while horizontal shifts are the OPPOSITE direction as the sign inside the parentheses, associated with
.
Consider the equation:
The vertex of this parabolic function would be located at:
Explanation
For any parabola, the general equation is
, and the x-coordinate of its vertex is given by
.
For the given problem, the x-coordinate is
.
To find the y-coordinate, plug into the original equation:
Therefore the vertex is at .
Red line
Blue line
Green line
Purple line
None of them
Explanation
A parabola is one example of a quadratic function, regardless of whether it points upwards or downwards.
The red line represents a quadratic function and will have a formula similar to .
The blue line represents a linear function and will have a formula similar to .
The green line represents an exponential function and will have a formula similar to .
The purple line represents an absolute value function and will have a formula similar to .
What is the domain of the following function? Please use interval notation.
Explanation
A basic knowledge of absolute value and its functions is valuable for this problem. However, if you do not know what the typical shape of an absoluate value function looks like, one can always plug in values and plot points.
Upon doing so, we learn that the -values (domain) are not restricted on either end of the function, creating a domain of negative infinity to postive infinity.
If we plug in -100000 for , we get 100000 for
.
If we plug in 100000 for , we get 100000 for
.
Additionally, if we plug in any value for , we will see that we always get a real, defined value for
.
**Extra Note: Due to the absolute value notation, the negative (-) next to the is not important, in that it will always be made positive by the absolute value, making this function the same as
. If the negative (-) was outside of the absolute value, this would flip the function, making all corresponding
-values negative. However, this knowledge is most important for range, rather than domain.
Explanation
All inputs are valid. There is nothing you can put in for x that won't work.
What is the domain of the function ?
Explanation
The expression under the square root symbol cannot be negative, so to find the domain, set that expression .
The domain includes all x-values less than or equal to 7, which can be written as .
What is the domain and range of the following graph?

Domain: All real numbers
Range:
Domain:
Range: All real numbers
Domain: All real numbers
Range:
Domain:
Range: All real numbers
Domain: All real numbers
Range: All real numbers
Explanation
Domain looks at x-values and range looks at y-values.
The x-values appear to continue to go on forever, which suggests the answer:
"all real numbers"
The y-values are all number that are equal to nine or less which is
So you answer is:
Domain: All real numbers
Range:
