# How do you prove l Hospital rule?

## How do you prove l Hospital rule?

To prove Macho L’Hospital’s Rule we first need a lemma: Souped Up Mean Value Theorem: If f(x) and g(x) are continuous on a closed interval [a,b] and differentiable on the open interval (a,b), then there is a point c, between a and b, where (f(b)−f(a))g′(c)=(g(b)−g(a))f′(c).

## How do you verify Cauchy’s value theorem?

Proof. First of all, we note that the denominator in the left side of the Cauchy formula is not zero: g(b)−g(a)≠0. Indeed, if g(b)=g(a), then by Rolle’s theorem, there is a point d∈(a,b), in which g′(d)=0. This, however, contradicts the hypothesis that g′(x)≠0 for all x∈(a,b).

What is the condition on a function to apply l hospital rule?

We can only apply the L’Hospital rule if the direct substitution returns an indeterminate form, that means 0/0 or ±∞/±∞.

### What is L Hospital rule used for?

L’hopital’s rule is used primarily for finding the limit as x→a of a function of the form f(x)g(x) , when the limits of f and g at a are such that f(a)g(a) results in an indeterminate form, such as 00 or ∞∞ .

### What happens when the limit is 0 0?

On a side note, the 0/0 we initially got in the previous example is called an indeterminate form. This means that we don’t really know what it will be until we do some more work. Typically, zero in the denominator means it’s undefined.

Does L Hospital rule always work?

L’Hospital’s Rule won’t work on products, it only works on quotients. However, we can turn this into a fraction if we rewrite things a little. The function is the same, just rewritten, and the limit is now in the form −∞/∞ − ∞ / ∞ and we can now use L’Hospital’s Rule.

#### What is the physical meaning of Cauchy’s Theorem?

1. Cauchy’s theorem. Simply-connected regions. A region is said to be simply-connected if any closed curve in that region can be shrunk to a point without any part of it leaving a region. The interior of a square or a circle are examples of simply connected regions.

#### What does Rolle’s theorem say?

Rolle’s theorem states that if a function f is continuous on the closed interval [a, b] and differentiable on the open interval (a, b) such that f(a) = f(b), then f′(x) = 0 for some x with a ≤ x ≤ b.

What if L Hopital’s rule doesn’t work?

l’Hopital’s Rule occationally fails by falling into a never ending cycle. Let us look at the following limit. As you can see, the limit came back to the original limit after applying l’Hopital’s Rule twice, which means that it will never yield a conclusion.

## How does L Hopital’s rule work?

So, L’Hospital’s Rule tells us that if we have an indeterminate form 0/0 or ∞/∞ all we need to do is differentiate the numerator and differentiate the denominator and then take the limit.

## Does 0 0 have a limit?

When simply evaluating an equation 0/0 is undefined. However, in taking the limit, if we get 0/0 we can get a variety of answers and the only way to know which on is correct is to actually compute the limit.

Is 0 0 infinite or no solution?

For an answer to have an infinite solution, the two equations when you solve will equal 0=0 . Here is a problem that has an infinite number of solutions. If you solve this your answer would be 0=0 this means the problem has an infinite number of solutions.