- #1
Zerius
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Homework Statement
lim sqrt(x-9)-3
x->0 sqrt(x)
Homework Equations
l'hop?
The Attempt at a Solution
as far as i got was conjugate the top and arriving somewhere where it is still undefined. =(
Zerius said:Homework Statement
lim sqrt(x-9)-3
x->0 sqrt(x)
Homework Equations
l'hop?
The Attempt at a Solution
as far as i got was conjugate the top and arriving somewhere where it is still undefined. =(
TD said:Because 1/x² exists in a neighbourhood arround x=0, that's not the case for e.g. sqrt(x-9).
I'm assuming the OP is studying limits of real-valued functions with a subset of the reals as domain.franznietzsche said:You can have complex numbers as answers. I just wouldn't expect it in a first course in differential calculus.
The original question (with sqrt(x-9) and x to zero) makes no sense, not even when you're talking about left- or right-handed limits. But if you're looking at sqrt(x), which is not defined for x<0, then you could say you're dealing with a right-handed limit. It really depends on how (formal) you defined the limit. It's certainly possible to talk about "the limit" in such a case, if you're restricting the values you're looking at to the intersection of a neighbourhood arround x=a and the domain of the function (without a itself). Then, in a case like sqrt(x), the definition already "tells you" you're only looking at x>0. I'm not sure if I'm being very clearJG89 said:TD, you're right. Strictly speaking about the set of real numbers, should the OP's question really be asking for a right-handed limit?
A limit of a function is the value that a function approaches as the input approaches a certain value. It represents the behavior of the function near that input value.
Yes, a limit of a function can exist even if the function itself does not exist at that point. This is because the limit only considers the behavior of the function near that point, not the actual value at that point.
To determine the limit of a function where it does not exist, you can use the left-hand and right-hand limits. If both the left-hand and right-hand limits approach the same value, then that value is the limit of the function. If they approach different values, then the limit does not exist.
Understanding the concept of a limit of a function is important because it allows us to analyze the behavior of a function near a certain point, even if the function is not defined at that point. This is useful in many mathematical and scientific applications.
Yes, there are many real-world applications of taking the limit of a function where it does not exist. For example, in physics, limits are used to analyze the behavior of a system as it approaches a certain state or condition. In economics, limits are used to analyze the behavior of a market as it approaches certain levels of supply and demand. In engineering, limits are used to analyze the behavior of a system as it approaches its maximum capacity.