Limit rational function without L'H

In summary, the conversation discusses finding the limit of a function using l'Hopital's Rule and suggests using other methods such as switching the order of the limit operation and the function, as well as using the continuity of square root for positive arguments.
  • #1
whatlifeforme
219
0

Homework Statement


evaluate.


Homework Equations


[itex]lim_{x->0+} \frac{\sqrt{x}}{\sqrt{sinx}}[/itex]


The Attempt at a Solution


i've tried l'hopital's and it is just endless cycle.
 
Physics news on Phys.org
  • #2
It's the same as sqrt(x/sin(x)). You know the limit of x/sin(x), right?
 
  • #3
whatlifeforme said:

Homework Statement


evaluate.


Homework Equations


[itex]lim_{x->0+} \frac{\sqrt{x}}{\sqrt{sinx}}[/itex]


The Attempt at a Solution


i've tried l'hopital's and it is just endless cycle.
Sometimes, L'Hopital's Rule is not the way to go. Under the right conditions, you can switch the order of the limit operation and the function in the limit.
## \lim f(g(x)) = f(\lim g(x))##

Also, as long as all quantities are positive,
$$ \frac{\sqrt{a}}{\sqrt{b}} = \sqrt{\frac{a}{b}}$$
 
  • #4
yes, but it is of the form 0/0.
 
  • #5
whatlifeforme said:
yes, but it is of the form 0/0.

That doesn't mean you HAVE to use l'Hopital. You know the limit of x/sin(x), use l'Hopital on that. Then take the square root. Use that the square root is continuous for positive arguments.
 

FAQ: Limit rational function without L'H

How can you simplify a limit rational function without using L'Hopital's rule?

The most common method for simplifying a limit rational function without L'Hopital's rule is to factor the numerator and denominator, and then cancel out any common factors. This can help to reduce the complexity of the function and make it easier to evaluate the limit.

Can you use substitution to solve a limit rational function without L'Hopital's rule?

Yes, substitution can also be used to simplify a limit rational function without L'Hopital's rule. This involves substituting a given value for the variable in the function, which can help to simplify the expression and make it easier to evaluate the limit.

Are there any other algebraic methods for solving limit rational functions?

Yes, there are several other algebraic methods that can be used to solve limit rational functions without L'Hopital's rule. These include using the properties of limits, applying the squeeze theorem, and using the binomial theorem.

When should I use L'Hopital's rule to solve a limit rational function?

L'Hopital's rule should only be used when the limit of a rational function results in an indeterminate form, such as 0/0 or ∞/∞. If the limit does not result in an indeterminate form, then it can be solved using other algebraic methods without having to use L'Hopital's rule.

Can I use a graphing calculator to solve a limit rational function without L'Hopital's rule?

Yes, a graphing calculator can be a useful tool for solving limit rational functions without L'Hopital's rule. By graphing the function and examining the behavior of the graph near the limit point, you can estimate the limit without having to use complex algebraic methods.

Similar threads

Replies
7
Views
868
Replies
10
Views
1K
Replies
2
Views
801
Replies
5
Views
971
Replies
8
Views
1K
Replies
8
Views
1K
Replies
14
Views
2K
Back
Top