#How to solve asymptotes using limits
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Bennxy
Hello, you have to take the limit as x approaches ∞
In this case, the limit doesn't converge, so there are no horizontal asymptotes
How to solve asymptotes using limits
An oblique asymptote is not a horizontal asymptote. To find an oblique asymptote, you need to write f(x) = mx+ b + g(x) where g(x) has a horizontal asymptote of y=0. Then y=mx+b is the oblique asymptote.
Fortunately, f(x) is already written that way for us, so you can just read off the oblique asymptote.
Ohh ok but when we used the limit for f(x) why didn't we divide 25x by x?
The 25x is separated by the plus sign.
So you mean this when we use limits to find the oblique asymptote?
$25x + \lim_{x \rightarrow \infty}20\cdot\frac{\left(\frac{50}{x^2+1}\right)}{x}$
Bennxy
Do we only apply the limit at infinity for the fraction, and not to other terms?
Yes, and it approaches 0
i think it applies to all terms
Follow what O Dog said. In this case, you have separated the linear term. The rest of the expression approaches 0, so the linear term is the oblique asymptote
If you had something like 25x + x², then there's no oblique asymptote because x² approaches inf
Aha ok
So do we apply the limit at infinity for 25x or not?
Because if we do we will get 25*inf
Or do we need to divide by x?
How does that work?
Really, you don't apply the limit at all.
Do this. If you really want to apply a limit, you should do it on the side to prove that g(x) goes to 0.
Ohh ok
I saw this a while ago and thought that we should use the limit over the whole function
Does anyone have any resources for this topic?
That image is the same as what I said. You can do that if you prefer.
Hahaha damn sorry man, that image looked more obvious with the functions and stuff
Do you have any resources on this topic that I can learn from?
Khan academy: oblique asymptotes is my best guess.
Ok I'll check it out thanks
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