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Example Questions
Example Question #2 : Rational Functions
Which is a vertical asymptote of the graph of the function ?
(a)
(b)
(a) only
(b) only
Both (a) and (b)
Neither (a) nor (b)
(b) only
The vertical asymptote(s) of the graph of a rational function such as can be found by evaluating the zeroes of the denominator after the rational expression is reduced. The expression is in simplest form, so set the denominator equal to 0 and solve for :
The graph of the line is the only vertical asymptote of the graph of .
Example Question #1 : Rational Functions
Give the equation(s) of the vertical asymptote(s) of the graph of the function
.
The graph of has no vertical asymptotes.
and
The vertical asymptote(s) of the graph of a rational function such as can be found by evaluating the zeroes of the denominator.
Set the denominator equal to 0 and solve for :
The only vertical asymptote of the graph is the line of the equation .
Example Question #2 : Rational Functions
Give the -coordinate of the -intercept the graph of the function
.
The graph of has no -intercept.
The graph of has no -intercept.
The -intercept of the graph of a function is the point at which it intersects the -axis. The -coordinate is 0, so the -coordinate can be found by evaluating . This is done by substitution, as follows:
The value of the denominator here is 0, so is an undefined quantity. Consequently, the graph of has no -intercept.
Example Question #2 : Rational Functions
Which is a vertical asymptote of the graph of the function
?
(a)
(b)
Neither (a) nor (b)
Both (a) and (b)
(b) only
(a) only
(a) only
The vertical asymptote(s) of the graph of a rational function such as can be found by evaluating the zeroes of the denominator after the rational expression is reduced.
First, factor the numerator and denominator.
The numerator is a perfect square trinomial and can be factored as such:
The denominator can be factored as the difference of squares:
Rewrite
as
The expression can be reduced by cancelling in both halves:
Set the denominator equal to 0 and solve:
The only vertical asymptote is therefore the line of the equation .
Example Question #3 : Rational Functions
Which of the following is a vertical asymptote of the graph of the function ?
(a)
(b)
Neither (a) nor (b)
Both (a) and (b)
(b) only
(a) only
Neither (a) nor (b)
The vertical asymptote(s) of the graph of a rational function such as can be found by evaluating the zeroes of the denominator after the rational expression is reduced.
First, factor the numerator. It is a quadratic trinomial with lead term , so look to "reverse-FOIL" it as
We seek two integers whose sum is and whose product is ; through trial and error, we find and 2, so
Therefore, can be rewritten as
Cancelling , this can be seen to be essentially a polynomial function:
which does not have a vertical asymptote.
Example Question #5 : Rational Functions
Give the -coordinate(s) of the -intercept(s) the graph of the function .
The graph of has no -intercept.
The -intercept(s) of the graph of are the point(s) at which it intersects the -axis. The -coordinate of each is 0; their -coordinate(s) are those value(s) of for which , so set up, and solve for , the equation:
A fraction is equal to 0 if and only if the numerator is equal to 0, so set
Factor out :
By the Zero Product Property, one of the factors must be equal to 0, so either
or
in which case
.
However, setting in the definition, we see that
, an undefined expression due to the zero denominator. 5 cannot be eliminated similarly. Therefore, is the only -intercept.
Example Question #1 : Miscellaneous Functions
Define a function .
Which statement correctly gives ?
The inverse function of a function can be found as follows:
Replace with :
Switch the positions of and :
or
Solve for . This can be done as follows:
Square both sides:
Add 9 to both sides:
Multiply both sides by , distributing on the right:
Replace with :
Example Question #81 : Graphs
Refer to the above diagram, which shows the graph of a function .
True or false: .
True
False
False
The statement is false. Look for the point on the graph of with -coordinate by going right unit, then moving up and noting the -value, as follows:
, so the statement is false.
Example Question #1 : Miscellaneous Functions
The above diagram shows the graph of function on the coordinate axes. True or false: The -intercept of the graph is
False
True
False
The -intercept of the graph of a function is the point at which it intersects the -axis (the vertical axis). That point is marked on the diagram below:
The point is about one and three-fourths units above the origin, making the coordinates of the -intercept .
Example Question #3 : Miscellaneous Functions
A function is defined on the domain according to the above table.
Define a function . Which of the following values is not in the range of the function ?
This is the composition of two functions. By definition, . To find the range of , we need to find the values of this function for each value in the domain of . Since , this is equivalent to evaluating for each value in the range of , as follows:
Range value: 3
Range value: 5
Range value: 8
Range value: 13
Range value: 21
The range of on the set of range values of - and consequently, the range of - is the set . Of the five choices, only 45 does not appear in this set; this is the correct choice.
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