All GRE Subject Test: Math Resources
Example Questions
Example Question #33 : New Concepts
Evaluate the following limit:
The limit does not exist
When we evaluate the limit using normal methods, we get , an indeterminate form. So, to evaluate the limit, we must use L'Hopital's Rule, which states that when we receive the indeterminate form of the type above (or ):
So, we must find the derivative of the top and bottom functions:
,
The derivatives were found using the following rules:
, ,
Now, rewrite the limit and evaluate:
Example Question #34 : New Concepts
Evaluate the limit:
The limit does not exist
When evaluating the limit using normal methods, we get the indeterminate form . When this occurs, or when occurs, we must use L'Hopital's Rule to evaluate the limit. The rules states
So, we must find the derivative of the numerator and denominator:
The derivatives were found using the following rules:
, ,
Now, using the above formula, evaluate the limit:
Example Question #11 : L'hospital's Rule
Find the limit if it exists.
Hint: Apply L'Hospital's Rule.
Through direct substitution, we see that the limit becomes
which is in indeterminate form.
As such we can use l'Hospital's Rule, which states that if the limit
is in indeterminate form, then the limit is equivalent to
Taking the derivatives we use the power rule which states
Using the power rule the limit becomes
As such the limit exists and is
Example Question #22 : Limits
Find the limit if it exists.
Hint: Apply L'Hospital's Rule.
Through direct substitution, we see that the limit becomes
which is in indeterminate form.
As such we can use l'Hospital's Rule, which states that if the limit
is in indeterminate form, then the limit is equivalent to
Taking the derivatives we use the trigonometric rule which states
where is a constant.
Using l'Hospital's Rule we obtain
And through direct substitution we find
As such the limit exists and is
Example Question #21 : L'hospital's Rule
Evaluate the following limit:
The limit does not exist
When evaluting the limit using normal methods, we find that the indeterminate form is reached. When this (or ) happens, we use L'Hopital's Rule to evaluate the limit:
So, we must find the derivative of the numerator and denominator:
When we plug these into the formula and evaluate the limit we get:
Example Question #41 : New Concepts
Find using L'Hospital's Rule.
None of the other choices
We being by attempted to plug in into our given function.
Since this would yield , we can use L'Hospital's Rule to help us find the limit.
Replace the numerator and the denominator of our function with their respective derivatives, and we get
Hence the answer is .
Example Question #21 : Limits
Find the limit:
By substituting the value of , we will find that this will give us the indeterminate form . This means that we can use L'Hopital's rule to solve this problem.
L'Hopital states that we can take the limit of the fraction of the derivative of the numerator over the derivative of the denominator. L'Hopital's rule can be repeated as long as we have an indeterminate form after every substitution.
Take the derivative of the numerator.
Take the derivative of the numerator.
Rewrite the limit and use substitution.
The limit is .
Example Question #43 : New Concepts
Find the limit if it exists
Hint: Use L'Hospital's rule
Directly evaluating for yields the indeterminate form
we are able to apply L'Hospital's rule which states that if the limit is in indeterminate form when evaluated, then
As such the limit in the problem becomes
Evaluating for again yields the indeterminate form
So we apply L'Hospital's rule again
Evaluating for yields
As such
and thus
Example Question #21 : L'hospital's Rule
Find the limit if it exists
Hint: Use L'Hospital's rule
Directly evaluating for yields the indeterminate form
we are able to apply L'Hospital's rule which states that if the limit is in indeterminate form when evaluated, then
As such the limit in the problem becomes
Evaluating for yields
As such
and thus
Example Question #44 : New Concepts
Evaluate the following limit:
The limit does not exist
When we evaluate the limit using normal methods, we arrive at the indeterminate form . When this occurs, to evaluate the limit, we must use L'Hopital's Rule, which states that
So, we must find the derivative of the top and bottom functions:
The derivatives were found using the following rule:
Now, rewrite the limit and evaluate it:
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