4.7 L'Hopital's Rule

Front

What is L'Hopital's Rule?

Back

L'Hopital's Rule is a method for finding the limit of indeterminate forms (0/0 or ∞/∞) by differentiating the numerator and denominator.

Front

When can L'Hopital's Rule be applied?

Back

L'Hopital's Rule can be applied when evaluating limits that result in indeterminate forms such as 0/0 or ∞/∞.

Front

State the formula for L'Hopital's Rule.

Back

If lim (x -> c) f(x) = 0 and lim (x -> c) g(x) = 0 (or both approach ∞), then: lim (x -> c) (f(x)/g(x)) = lim (x -> c) (f'(x)/g'(x)) provided the limit on the right exists.

Front

What is an indeterminate form?

Back

An indeterminate form is an expression that does not have a well-defined limit, such as 0/0, ∞/∞, 0×∞, ∞ - ∞, 0^0, ∞^0, or 1^∞.

Front

Provide an example of using L'Hopital's Rule.

Back

Example: lim (x -> 0) (sin x / x) = 0/0. Applying L'Hopital's Rule: lim (x -> 0) (cos x / 1) = 1.

Front

What is the first step in applying L'Hopital's Rule?

Back

The first step is to confirm that the limit results in an indeterminate form (0/0 or ∞/∞).

Front

Can L'Hopital's Rule be applied multiple times?

Back

Yes, L'Hopital's Rule can be applied multiple times if the resulting limit after the first application is still an indeterminate form.

Front

What is the derivative of sin x?

Back

The derivative of sin x is cos x.

Front

What is the derivative of e^x?

Back

The derivative of e^x is e^x.

Front

What is the derivative of ln x?

Back

The derivative of ln x is 1/x.