Functions and Graphs
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Math › 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." )

The above table shows a function with domain .
True or false: has an inverse function.
False
True
Explanation
A function has an inverse function if and only if, for all
in the domain of
, if
, it follows that
. In other words, no two values in the domain can be matched with the same range value.
If we order the rows by range value, we see this to not be the case:

and
. Since two range values exist to which more than one domain value is matched, the function has no inverse.
What are the -intercepts of the equation?
There are no -intercepts.
Explanation
To find the x-intercepts of the equation, we set the numerator equal to zero.
What are the coordinates of the center of a circle with the equation ?
Explanation
The equation of a circle is , in which (h, k) is the center of the circle. To derive the center of a circle from its equation, identify the constants immediately following x and y, and flip their signs. In the given equation, x is followed by -1 and y is followed by -6, so the coordinates of the center must be (1, 6).
Find the slope of the following equation:
Explanation
To find the slope for a given equation, it needs to first be put into the "y=mx+b" format. Then our slope is the number in front of the x, or the "m". For this equation this looks as follows:
First subtract 2x from both sides:
That gives us the following:
Divide all three terms by three to get "y" by itself:
This means our "m" is -2/3
Which of the following is NOT a function?
Explanation
A function has to pass the vertical line test, which means that a vertical line can only cross the function one time. To put it another way, for any given value of , there can only be one value of
. For the function
, there is one
value for two possible
values. For instance, if
, then
. But if
,
as well. This function fails the vertical line test. The other functions listed are a line,
, the top half of a right facing parabola,
, a cubic equation,
, and a semicircle,
. These will all pass the vertical line test.
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.
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
.
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 .
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 .
