Precalculus Examples

Find the Asymptotes (3(2x+7)(x+8))/(x+1)
Step 1
Find where the expression is undefined.
Step 2
Consider the rational function where is the degree of the numerator and is the degree of the denominator.
1. If , then the x-axis, , is the horizontal asymptote.
2. If , then the horizontal asymptote is the line .
3. If , then there is no horizontal asymptote (there is an oblique asymptote).
Step 3
Find and .
Step 4
Since , there is no horizontal asymptote.
No Horizontal Asymptotes
Step 5
Find the oblique asymptote using polynomial division.
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Step 5.1
Simplify the numerator.
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Step 5.1.1
Factor out of .
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Step 5.1.1.1
Factor out of .
Step 5.1.1.2
Factor out of .
Step 5.1.1.3
Factor out of .
Step 5.1.1.4
Factor out of .
Step 5.1.1.5
Factor out of .
Step 5.1.2
Factor by grouping.
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Step 5.1.2.1
For a polynomial of the form , rewrite the middle term as a sum of two terms whose product is and whose sum is .
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Step 5.1.2.1.1
Factor out of .
Step 5.1.2.1.2
Rewrite as plus
Step 5.1.2.1.3
Apply the distributive property.
Step 5.1.2.2
Factor out the greatest common factor from each group.
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Step 5.1.2.2.1
Group the first two terms and the last two terms.
Step 5.1.2.2.2
Factor out the greatest common factor (GCF) from each group.
Step 5.1.2.3
Factor the polynomial by factoring out the greatest common factor, .
Step 5.2
Expand .
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Step 5.2.1
Apply the distributive property.
Step 5.2.2
Apply the distributive property.
Step 5.2.3
Apply the distributive property.
Step 5.2.4
Apply the distributive property.
Step 5.2.5
Remove parentheses.
Step 5.2.6
Remove parentheses.
Step 5.2.7
Move .
Step 5.2.8
Multiply by .
Step 5.2.9
Raise to the power of .
Step 5.2.10
Raise to the power of .
Step 5.2.11
Use the power rule to combine exponents.
Step 5.2.12
Add and .
Step 5.2.13
Multiply by .
Step 5.2.14
Multiply by .
Step 5.2.15
Multiply by .
Step 5.2.16
Multiply by .
Step 5.2.17
Multiply by .
Step 5.2.18
Add and .
Step 5.3
Set up the polynomials to be divided. If there is not a term for every exponent, insert one with a value of .
+++
Step 5.4
Divide the highest order term in the dividend by the highest order term in divisor .
+++
Step 5.5
Multiply the new quotient term by the divisor.
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++
Step 5.6
The expression needs to be subtracted from the dividend, so change all the signs in
+++
--
Step 5.7
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
+++
--
+
Step 5.8
Pull the next terms from the original dividend down into the current dividend.
+++
--
++
Step 5.9
Divide the highest order term in the dividend by the highest order term in divisor .
+
+++
--
++
Step 5.10
Multiply the new quotient term by the divisor.
+
+++
--
++
++
Step 5.11
The expression needs to be subtracted from the dividend, so change all the signs in
+
+++
--
++
--
Step 5.12
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
+
+++
--
++
--
+
Step 5.13
The final answer is the quotient plus the remainder over the divisor.
Step 5.14
The oblique asymptote is the polynomial portion of the long division result.
Step 6
This is the set of all asymptotes.
Vertical Asymptotes:
No Horizontal Asymptotes
Oblique Asymptotes:
Step 7