The rational function is .
First graph the function.
\The rational function .
Factor the numerator and denominator of . Find the domain of the rational function :
The domain of a rational function is the set of all real numbers for which the function is mathematically correct.
\Denominator of the function should not be zero.
\ and
and
.
The domain of function is
.
Write in lowest terms :
The function is .
.
The function is in lowest terms.
The rational function .
\
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Locate the intercepts of the graph and determine the behavior of the graph of near each
- intercept :
Change to
.
Find the intercepts.
\Find the -intercept by equating
to zero.
Determine the behaviour of the graph of near each
-intercept.
Near :
.
Plot the point and indicate a line with negative slope.
Find the intercept, by substituting
in the rational function.
There is no -intercepts.
\
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Determine the vertical asymptotes :
\Vertical asymptote can be found by making denominator to zero.
\ or
or
.
\
Determine the horizantal asymptotes / oblique asymptotes :
\To find horizontal asymptote, first find the degree of the numerator and the degree of denominator.
\Degree of numerator, Degree of the denominator
.
Since the degree of the numerator is less than the degree of the denominator,
\hence horizontal asymptote is .
Use the zeros of the numerator and denominator of to divide the
-axis into intervals :
The real zero of numerator is and the real zeros of denominator
and
.
So divide the - axis into four intervals.
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Interval | \ \
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Location of the graph | \
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Below the \ | \
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Above the \ | \
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Below the \ | \
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Above the | \
End behavior of the graph :
\As and
, hence the graph of
approaches to a vertical asymptote at
.
As and
, hence the graph of
approaches to a vertical asymptote at
.
As and
, hence the graph of
approaches to a horizontal asymptote at
.
Use the results obtained in Steps 1 through 7 to graph the function :
\Draw the coordinate plane.
\Plot the horizontal and vertical asymptotes.
\Plot the and
intercepts and coordinate pairs found in the table.
Connect the plotted points to smooth curve.
\\
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First determine the intervals of -such that the graph is above the
- axis from the graph.
The graph of the function is above the
- axis on the intervals
or
From the graph, for
.
The solution set is or in interval notation,
.
;
.