All Calculus 2 Resources
Example Questions
Example Question #5 : Harmonic Series
Does the following series converge?
Cannot be determined
No
Yes
No
No the series does not converge. The given problem is the harmonic series, which diverges to infinity.
Example Question #6 : Harmonic Series
Does the following series converge?
No
Yes
Cannot be determined
Yes
The series converges. The given problem is the alternating harmonic series, which converges by the alternating series test.
Example Question #7 : Harmonic Series
Which of the following tests can be used to (successfully) test for the convergence/divergence of the harmonic series?
The Limit Test for Divergence
The Root Test
None of the given tests can be used.
The Ratio Test
The Integral Test
The Integral Test
Only the Integral Test will work on the Harmonic Series, .
To use the Integral Test, we evaluate
, which shows that the series diverges.
Since , the Limit Test for Divergence fails.
The Ratio Test and the Root Test will always yield the same conclusion, so if one test fails, the both fail and vise versa.
For the Ratio Test,
. Since the result of the limit is , both tests fail.
Example Question #8 : Harmonic Series
Let's say you are given harmonic series in the following form:
;
You are then asked to determine if the series converges, or diverges. For what values of p would this series be convergent? Assume p>0.
The given series is called generalized harmonic series.
The series converges, if , and diverges, if .
Example Question #1 : Alternating Series
By definition, an Alternating Series is a series of the form-
None of the other answers
This type of series we can frequently check for convergence/divergence using the Alternating Series Test.
The terms with an odd value for become negative since and the terms with an even value for are positive. This creates the alternating signs to occur within the sum.
Example Question #3001 : Calculus Ii
Differentiate the following function.
To differentiate the function we will need to use the Power Rule which states:
Looking at our function we can first simplify the equation.
Applying the Power Rule we get:
Example Question #1 : Alternating Series
Does the series converge conditionally, absolutely, or diverge?
Converge Conditionally.
Cannot tell with the given information.
Diverges.
Does not exist.
Converge Absolutely.
Converge Conditionally.
The series converges conditionally.
The absolute values of the series is a divergent p-series with .
However, the the limit of the sequence and it is a decreasing sequence.
Therefore, by the alternating series test, the series converges conditionally.
Example Question #1 : Alternating Series
Find the interval of convergence of for the series .
Using the root test,
Because 0 is always less than 1, the root test shows that the series converges for any value of x.
Therefore, the interval of convergence is:
Example Question #2 : Alternating Series
Determine whether
converges or diverges, and explain why.
Divergent, by the test for divergence.
Convergent, by the alternating series test.
Divergent, by the comparison test.
More tests are needed.
Convergent, by the -series test.
Convergent, by the alternating series test.
We can use the alternating series test to show that
converges.
We must have for in order to use this test. This is easy to see because is in for all (the values of this sequence are ), and sine is always nonzero whenever sine's argument is in .
Now we must show that
1.
2. is a decreasing sequence.
The limit
implies that
so the first condition is satisfied.
We can show that is decreasing by taking its derivative and showing that it is less than for :
The derivative is less than , because is always less than , and that is positive for , using a similar argument we used to prove that for . Since the derivative is less than , is a decreasing sequence. Now we have shown that the two conditions are satisfied, so we have proven that
converges, by the alternating series test.
Example Question #3 : Alternating Series
For the series: , determine if the series converge or diverge. If it diverges, choose the best reason.
The series given is an alternating series.
Write the three rules that are used to satisfy convergence in an alternating series test.
For :
The first and second conditions are satisfied since the terms are positive and are decreasing after each term.
However, the third condition is not valid since and instead approaches infinity.
The correct answer is:
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