The rational function .
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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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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Vertical asymptote can be found by making denominator to zero.
\ or
or
.
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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 .
The real zero of numerator is and the real zeros of denominator
and
.
So divide the - axis into four intervals.
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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 | \
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
.
Graph :
\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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The domain of function is
.
The rational function in lowest terms .
-intercept is
.
There is no -intercepts.
Vertical asymptote are or
.
Horizontal asymptote is .
Interval | \ \
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Above the \ | \
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Below the \ | \
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Above the | \
Graph of the rational function .
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