AP Calculus BC : AP Calculus BC

Study concepts, example questions & explanations for AP Calculus BC

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Example Questions

Example Question #11 : Series Of Constants

True or False, a -series cannot be tested conclusively using the ratio test.

Possible Answers:

False

True

Correct answer:

True

Explanation:

We cannot test for convergence of a -series using the ratio test. Observe,

For the series ,

.

Since this limit is  regardless of the value for , the ratio test is inconclusive.

Example Question #1 : Ratio Test And Comparing Series

Determine if the following series is divergent, convergent or neither.

Possible Answers:

Divergent

Inconclusive

Neither

Convergent

Both

Correct answer:

Convergent

Explanation:

In order to figure out if 

is divergent, convergent or neither, we need to use the ratio test.

Remember that the ratio test is as follows.

Suppose we have a series . We define,

 

Then if 

, the series is absolutely convergent.

, the series is divergent.

, the series may be divergent, conditionally convergent, or absolutely convergent.

Now lets apply the ratio test to our problem.

Let  

and

Now 

Now lets simplify this expression to 

.

Since 

.

We have sufficient evidence to conclude that the series is convergent.

Example Question #2 : Ratio Test And Comparing Series

Determine if the following series is divergent, convergent or neither.

 

Possible Answers:

Divergent

Convergent

Inconclusive

Both

Neither

Correct answer:

Divergent

Explanation:

In order to figure if 

is convergent, divergent or neither, we need to use the ratio test.

Remember that the ratio test is as follows.

Suppose we have a series . We define,

Then if 

, the series is absolutely convergent.

, the series is divergent.

, the series may be divergent, conditionally convergent, or absolutely convergent.

Now lets apply the ratio test to our problem.

Let  

and

Now 

.

Now lets simplify this expression to 

.

Since ,

we have sufficient evidence to conclude that the series is divergent.

 

Example Question #3 : Ratio Test And Comparing Series

Determine if the following series is divergent, convergent or neither.

Possible Answers:

Both

Neither

Inconclusive

Convergent

Divergent

Correct answer:

Divergent

Explanation:

In order to figure if 

is convergent, divergent or neither, we need to use the ratio test. 

Remember that the ratio test is as follows.

Suppose we have a series . We define,

Then if 

, the series is absolutely convergent.

, the series is divergent.

, the series may be divergent, conditionally convergent, or absolutely convergent.

Now lets apply the ratio test to our problem.

Let  

and

.

Now 

.

Now lets simplify this expression to 

.

Since ,

we have sufficient evidence to conclude that the series is divergent.

 

Example Question #4 : Ratio Test And Comparing Series

Determine if the following series is convergent, divergent or neither.

Possible Answers:

More tests are needed.

Convergent

Inconclusive

Divergent

Neither

Correct answer:

Divergent

Explanation:

To determine if

is convergent, divergent or neither, we need to use the ratio test.

The ratio test is as follows.

Suppose we a series  . Then we define,

.

If

  the series is absolutely convergent (and therefore convergent).

  the series is divergent.

 the series may be divergent, conditionally convergent, or absolutely convergent.

Now lets apply this to our situtation.

Let

and

Now

We can rearrange the expression to be

Now lets simplify this.

When we evaluate the limit, we get.

.

Since , we have sufficient evidence to conclude that the series diverges.

Example Question #5 : Ratio Test And Comparing Series

Determine if the following series is divergent, convergent or neither.

Possible Answers:

Divergent

Inconclusive

Neither

More tests are needed.

Convegent

Correct answer:

Convegent

Explanation:

To determine if

is convergent, divergent or neither, we need to use the ratio test.

The ratio test is as follows.

Suppose we a series  . Then we define,

.

If

  the series is absolutely convergent (and thus convergent).

  the series is divergent.

 the series may be divergent, conditionally convergent, or absolutely convergent.

Now lets apply this to our situtation.

Let

and

Now

We can rearrange the expression to be

.

Now lets simplify this.

When we evaluate the limit, we get.

.

Since , we have sufficient evidence to conclude that the series converges.

Example Question #71 : Convergence And Divergence

Determine if the following series is convergent, divergent or neither.

Possible Answers:

Inconclusive

More tests needed.

Convergent

Divergent

Neither

Correct answer:

Divergent

Explanation:

To determine if

is convergent, divergent or neither, we need to use the ratio test.

The ratio test is as follows.

Suppose we a series  . Then we define,

.

If

  the series is absolutely convergent (therefore convergent).

  the series is divergent.

 the series may be divergent, conditionally convergent, or absolutely convergent.

Now lets apply this to our situtation.

Let

and

Now

We can rearrange the expression to be

Now lets simplify this.

When we evaluate the limit, we get.

.

Since , we have sufficient evidence to conclude that the series diverges.

Example Question #7 : Ratio Test And Comparing Series

Determine if the following series is divergent, convergent or neither.

Possible Answers:

Inconclusive

Convergent

More tests are needed.

Divergent

Neither

Correct answer:

Divergent

Explanation:

To determine if

is convergent, divergent or neither, we need to use the ratio test.

The ratio test is as follows.

Suppose we a series  . Then we define,

.

If

  the series is absolutely convergent (and thus convergent).

  the series is divergent.

 the series may be divergent, conditionally convergent, or absolutely convergent.

Now lets apply this to our situtation.

Let

and

Now

We can simplify the expression to be

When we evaluate the limit, we get.

.

Since , we have sufficient evidence to conclude that the series diverges.

Example Question #8 : Ratio Test And Comparing Series

Determine of the following series is convergent, divergent or neither.

Possible Answers:

Inconclusive.

More tests are needed.

Neither

Divergent

Convergent

Correct answer:

Divergent

Explanation:

To determine whether this series is convergent, divergent or neither

we need to remember the ratio test.

The ratio test is as follows.

Suppose we a series  . Then we define,

.

If

  the series is absolutely convergent (and therefore convergent).

  the series is divergent.

 the series may be divergent, conditionally convergent, or absolutely convergent.

Now lets apply this to our situtation.

Let

and

Now

We can rearrange the expression to be

Now lets simplify this to.

When we evaluate the limit, we get.

.

Since , we have sufficient evidence to conclude that the series is divergent.

Example Question #9 : Ratio Test And Comparing Series

Determine what the following series converges to using the ratio test and whether the series is convergent, divergent or neither.

Possible Answers:

, and neither.

, and convergent.

, and divergent.

, and convergent.

, and neither.

Correct answer:

, and convergent.

Explanation:

To determine whether this series is convergent, divergent or neither

we need to remember the ratio test.

The ratio test is as follows.

Suppose we a series  . Then we define,

.

If

  the series is absolutely convergent (thus convergent).

  the series is divergent.

 the series may be divergent, conditionally convergent, or absolutely convergent.

Now lets apply this to our situtation.

Let

and

Now

We can rearrange the expression to be

Now lets simplify this to.

When we evaluate the limit, we get.

.

Since , we have sufficient evidence to conclude that the series is convergent.

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