Precalculus Examples

Graph f(x)=-2 log base 1/3 of x-1-1
Step 1
Find the asymptotes.
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Step 1.1
Find where the expression is undefined.
Step 1.2
Ignoring the logarithm, 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 1.3
There are no horizontal asymptotes because is .
No Horizontal Asymptotes
Step 1.4
No oblique asymptotes are present for logarithmic and trigonometric functions.
No Oblique Asymptotes
Step 1.5
This is the set of all asymptotes.
Vertical Asymptotes:
No Horizontal Asymptotes
Vertical Asymptotes:
No Horizontal Asymptotes
Step 2
Find the point at .
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Step 2.1
Replace the variable with in the expression.
Step 2.2
Simplify the result.
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Step 2.2.1
Simplify each term.
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Step 2.2.1.1
Subtract from .
Step 2.2.1.2
Logarithm base of is .
Step 2.2.1.3
Multiply by .
Step 2.2.2
Subtract from .
Step 2.2.3
The final answer is .
Step 2.3
Convert to decimal.
Step 3
Find the point at .
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Step 3.1
Replace the variable with in the expression.
Step 3.2
Simplify the result.
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Step 3.2.1
Simplify each term.
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Step 3.2.1.1
Subtract from .
Step 3.2.1.2
Logarithm base of is .
Step 3.2.1.3
Multiply by .
Step 3.2.2
Subtract from .
Step 3.2.3
The final answer is .
Step 3.3
Convert to decimal.
Step 4
Find the point at .
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Step 4.1
Replace the variable with in the expression.
Step 4.2
Simplify the result.
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Step 4.2.1
Simplify each term.
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Step 4.2.1.1
Subtract from .
Step 4.2.1.2
Logarithm base of is .
Step 4.2.1.3
Multiply by .
Step 4.2.2
Subtract from .
Step 4.2.3
The final answer is .
Step 4.3
Convert to decimal.
Step 5
The log function can be graphed using the vertical asymptote at and the points .
Vertical Asymptote:
Step 6