Math Problem Statement
A function is said to have a vertical asymptote wherever the limit on the left or right (or both) is either positive or negative infinity. For example, the function f(x)=−3(x+2)x2+4x+4 has a vertical asymptote at x=−2. Find each of the following limits. limx→−2−−3(x+2)x2+4x+4= help (limits)
limx→−2+−3(x+2)x2+4x+4= help (limits)
limx→−2−3(x+2)x2+4x+4= help (limits)
Solution
Let's analyze the limits of the given function at .
The function has a vertical asymptote at . This is because the denominator becomes 0 when . To find each limit, we'll evaluate the behavior of the function from both the left-hand side () and the right-hand side ().
1. Limit from the left
The denominator is . At , this denominator is 0 because . Since the denominator is squared, it will always be positive as we approach from either side, but the numerator depends on the behavior of .
- As , the term becomes a small negative number (just slightly less than 0).
- Therefore, becomes a small positive number (since the negative of a negative is positive).
Hence, as , the function behaves like:
Thus:
2. Limit from the right
Now, let's approach from the right-hand side ().
- As , the term becomes a small positive number (just slightly greater than 0).
- Therefore, becomes a small negative number.
Thus, as , the function behaves like:
Therefore:
3. Two-sided limit
Since the left-hand limit and right-hand limit as do not match (one approaches and the other approaches ), the two-sided limit does not exist.
Thus:
Summary:
Would you like further clarification or details on any of these steps?
Related Questions:
- How do vertical asymptotes affect the graph of a rational function?
- Can a function have more than one vertical asymptote?
- What is the difference between vertical and horizontal asymptotes?
- How do you find horizontal asymptotes of a rational function?
- What is the behavior of a function near a hole versus an asymptote?
Tip:
When dealing with rational functions, always factor the denominator and numerator completely to help locate vertical asymptotes and simplify limits.
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Math Problem Analysis
Mathematical Concepts
Limits
Rational Functions
Asymptotes
Infinity in Limits
Formulas
lim x→a f(x)
Vertical asymptote criteria (denominator approaching zero)
Theorems
Limits and Asymptotes
Behavior of Rational Functions near Vertical Asymptotes
Suitable Grade Level
Grades 10-12
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