Features of Rational Functions
A rational function R(x) is a function of the formshown, where P(x) and Q(x) are polynomials, and Q(x) is not the zero polynomial.
R(x) =
Q(x)
P(x)
A rational function is a function of the formshown, where Q(x) is not the zero polynomial.
h(x) = 
True or False:  The function shown below is a rational function:
x + 3
5x
False
True
P(x)
Q(x)
A rational function is a function of the formshown, where Q(x) is not the zero polynomial.
True or False:  The function shown below is a rational function:
g(x) =
x – 1
6
False
True
Q(x)
P(x)
A rational function is a function of the formshown, where Q(x) is not the zero polynomial.
True or False:  The function shown below is a rational function:
f(x) = 
x – 1
0
True
False
Q(x)
P(x)
A rational function is a function of the formshown, where Q(x) is not the zero polynomial.
The domain of a rational function is all real numbers except for the zeros of Q(x).
g(x) = 
x + 3
x – 2
What is the domain of g(x)?
x ≠ -3
x ≠ -2
x ≠ 2
x ≠ 3
P(x)
Q(x)
A rational function is a function of the formshown, where Q(x) is not the zero polynomial.
The domain of a rational function is all real numbers except for the zeros of Q(x).
h(x) = 
x(x+1)
x+1
What is the domain of h(x)?
x ≠ -1
x ≠ 0
x ≠ 1
All real numbers
Q(x)
P(x)
h(x) = 
The vertical asymptotes of R(x) will occur at the zeros of Q(x). So, if r is a zero for Q(x),  then x = r will be a vertical asymptote.
x(x+1)
x+2
Identify a vertical asymptote of h(x).
x = 1
x = 0
x = -1
x = -2
R(x) =
Q(x)
P(x)
k(x) = 
The vertical asymptotes of R(x) will occur at the zeros of Q(x). So, if r is a zero for Q(x),  then x = r will be a vertical asymptote.
-3x+9
2x
Identify a vertical asymptote of k(x).
x = 3
x = 2
x = 0
x = 1/2
R(x) =
Q(x)
P(x)
If the degree of the numerator = denominator, then thereis a horizontal asymptote at y = k, where k is the quotientof the leading coefficient of the numerator ÷ the leadingcoefficient of the denominator.
If the degree of the numerator > denominator, then thereis no horizontal asymptote.
Finding a horizontal asymptote:
If the degree of the numerator < denominator,then y = 0 is the horizontal asymptote.
R(x) =
Q(x)
P(x)
Finding a horizontal asymptote:
If the degree of the numerator < denominator,then y = 0 is the horizontal asymptote.
True or False: 
For the Rational Function given below, the horizontal asymptote is y = 0. 
f(x) =
5x2+ 3x
2x3
False
True
Finding a horizontal asymptote:
If the degree of the numerator < denominator,then y = 0 is the horizontal asymptote.
True or False: 
For the Rational Function given below, the horizontal asymptote is y = 0. 
f(x) =
(2x + 3)(x – 5)
(x + 1)2
False
True
True or False: 
For the Rational Function given below, the horizontal asymptote is y = 0. 
Finding a horizontal asymptote:
If the degree of the numerator < denominator,then y = 0 is the horizontal asymptote.
f(x) =
(2x+3)(x–5)
4x + 1
True
False
True or False: 
For the Rational Function given below, the horizontal asymptote is y = 2. 
Finding a horizontal asymptote:
If the degree of the numerator = denominator, then thereis a horizontal asymptote at y = k, where k = the leading coefficient of the numerator ÷ the leading coefficient of the denominator.
f(x) =
6x2 – 7x – 15
3x + 1
False
True
True or False: 
For the Rational Function given below, the horizontal asymptote is y = -8. 
Finding a horizontal asymptote:
If the degree of the numerator = denominator, then thereis a horizontal asymptote at y = k, where k = the leading coefficient of the numerator ÷ the leading coefficient of the denominator.
g(x) =
–12x2 + 3x +1
4x- 3x + 2
False
True
True or False: 
For the Rational Function given below, the x-intercept is x = -5 
Finding an x-intercept
To find the x-intercept, set y = 0.  Because it is a rational function, set the numerator = 0 and solve for x.
g(x) =
(x + 1)
x + 5
True
False
True or False: 
For the Rational Function given below, the x-intercept is x = -2. 
Finding an x-intercept
To find the x-intercept, set y = 0.  Because it is a rational function, set the numerator = 0 and solve for x.
g(x) =
(x – 2)(x – 3)
(x – 3)
True
False
True or False: 
For the Rational Function given below, the y-intercept is -1/5.
Finding a y-intercept
To find the y-intercept, set x = 0.  Because it is a rational function, set the numerator = 0 and solve for x.
g(x) =
2x – 1
3x + 5
True
False
Finding a y-intercept
To find the y-intercept, set x = 0.  
True or False: 
For the Rational Function given below, the y-intercept is 2/3.
y =
x – 2
x + 3
True
False
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