Limit Questions: Finding Solutions for Limits Problems

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In summary, the conversation revolves around finding limits, specifically for the following two questions: 1. lim h -> 0 ((3+h)^-1 - 3^-1)/h and 2. lim x -> -4- |x+4|/x+4. The experts suggest simplifying the expressions by finding a common denominator and using the fact that x < -4 to simplify the absolute value. After some discussion and corrections, the final answer for the first question is -1/9.
  • #1
powp
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can anybody help me with these two question for finding limits:

1. lim h -> 0 ((3+h)^-1 - 3^-1)/h
2. lim x -> -4- |x+4|/x+4


please help
 
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  • #2
1. looks an awful lot like the kind of limit you find in the definition of the derivative. If you haven't seen derivatives yet (or even if you have) try finding a common demoninator to simplify (3+h)^(-1) - 3^(-1)

2.you're interested in values of x that are less than -4. Use this to simplify the absolute value.
 
  • #3
for number one if I make it so that I only have positive exponents and simplify I end up with

1 /(9 + 3h) now if I plug in 0 the result is 1 / 9. Is this correct?
 
  • #4
I think you might have a sign error. Check this step in the numerator and tell me what you think:
(3-(3+h))/(9 + 3h) should distribute as (3-3-h)/(9 + 3h) or -h/(9 +3h)
 
  • #5
yeah it looks like I did make an error should be -1/9? right?
 
  • #6
That's what I got, but maybe one of the local mathletes will stop by and verify. :smile:
 

FAQ: Limit Questions: Finding Solutions for Limits Problems

1. What are limits in calculus?

Limits in calculus refer to the value that a function approaches as the input of the function gets closer and closer to a specific value. They are used to determine the behavior of a function near a certain point.

2. What are the common types of limits?

The most common types of limits are one-sided limits, where the input approaches the specific value from only one side, and two-sided limits, where the input approaches the specific value from both sides.

3. How do you find the limit of a function?

To find the limit of a function, you can either use algebraic methods such as factoring and canceling out common terms, or you can use graphical methods by plotting the function and observing its behavior near the specific value.

4. What are indeterminate forms in limits?

Indeterminate forms in limits occur when the limit of a function cannot be determined by direct substitution. These include forms such as 0/0, ∞/∞, and ∞ - ∞. They require additional algebraic manipulations or the use of L'Hopital's rule to solve.

5. Why are limits important in mathematics?

Limits are important in mathematics because they allow us to understand the behavior of functions and make precise calculations even when the function is not defined at a certain point. They are also crucial in many real-life applications, such as in economics and physics.

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