Exploring Why Limit Approaches -∞ for ln(x^2-9)

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In summary, when a limit approaches negative infinity, the function is decreasing without bound. This relates to ln(x^2-9) because the natural logarithm function is only defined for positive inputs, so as x approaches negative infinity, the expression (x^2-9) becomes positive and allows us to take the natural logarithm. The result of taking the limit as x approaches negative infinity for ln(x^2-9) is negative infinity, and there is a restriction on the input for the function. We can use this limit to find the asymptotes of ln(x^2-9) by setting the limit equal to the vertical asymptote at x = -∞.
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CrossFit415
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I'm on mobile so I won't use latex.

Lim x -> 3 ln(x^2-9)

My question is why limit approaches - infinite? When I plug in the numbers I get positive infinite.
 
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How did you get positive infinite?? Can you show me what you did?
 
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Since I have to figure out x>3, I plugged in the values such as x=4 y=1.945, x=3.5 y=1.178, x=3.9 y=1.826. Whoops I found my mistake haha. I kept plugging in 3.9 and 3.9999 thinking it was closer to 3, when I should had plugged in 3.01 and 3.001. Thank you.
 

1. What does it mean for a limit to approach negative infinity?

When a limit approaches negative infinity, it means that the value of the function is becoming increasingly negative as the input approaches negative infinity. In other words, the function is decreasing without bound.

2. How does this relate to ln(x^2-9)?

The natural logarithm function, ln(x), is undefined for negative inputs. Therefore, when we take the natural logarithm of (x^2-9), we are restricted to values of x that make the expression positive. As x approaches negative infinity, the expression (x^2-9) approaches positive infinity, allowing us to take the natural logarithm.

3. What is the result of taking the limit as x approaches negative infinity for ln(x^2-9)?

The result of taking the limit as x approaches negative infinity for ln(x^2-9) is negative infinity. This is because the function becomes increasingly negative as x approaches negative infinity, and the natural logarithm of a value approaching infinity is also infinity.

4. Are there any restrictions on the input for ln(x^2-9) when taking the limit as x approaches negative infinity?

Yes, there is a restriction on the input for ln(x^2-9) when taking the limit as x approaches negative infinity. The expression (x^2-9) must be positive in order for us to take the natural logarithm. This means that x must be greater than -3 or less than 3.

5. How can we use this limit to find the asymptotes of ln(x^2-9)?

To find the asymptotes of ln(x^2-9), we can set the limit as x approaches negative infinity equal to the vertical asymptote. In this case, the limit as x approaches negative infinity is equal to -∞, so the vertical asymptote is at x = -∞. This means that the graph of ln(x^2-9) approaches the vertical line x = -∞ as x decreases without bound.

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