Test III Review Sheet for
Colorado State University, Pueblo
Math 224 — Calculus II — Fall 2014
Definitions/Theorems/Ideas:
- sequences: recurrence relation, explicit formula
- limit of a sequence: both general idea (convergent and
divergent) and formal definition
- geometric sequence
- limit laws for sequences
- squeeze theorem for sequences
- bounded monotonic sequences and their convergence
- series
- limit of s series: idea in terms of limit of the sequence of
partial sums; convergent and divergent, again.
- geometric series and when it converges and to what
- telescoping series
- tests about convergence of series:
- the divergence test
- the integral test
- the ratio test
- the root test
- the comparison test
- the limit comparison test
- the alternating series test
Always check all their hypotheses
- alternating series
- the harmonic and alternating harmonic series
- absolute and conditional convergence of series
- approximating functions with polynomials: linear,
quadratic, and higher-order approximations
- then remainder of a Taylor polynomial
- a power series [centered at $x=a$]
- Taylor's Theorem
- estimating error in power series
- the theorem about convergence of a power series: Interval
and Radius of convergence (IoC and RoC)
- the theorem(s) about operations on power series: CMR,
addition, multiplication, composition, division,
differentiation, integration, etc.
- the Taylor series and Maclaurin series of a function
- binomial series and the binomial coefficient
- more specific applications of power series:
- limits
- representing real numbers as series
- solving differential equations
- representing functions as power series and, conversely,
finding the function represented by a power series
You must be able to define, work with, recognize, and apply all of the above.
Specific things not to forget:
- Always check all the hypotheses of a test you use.
- Know how to prove from the formal definition the value of a sequence
limit.
- Usually we have to check the endpoints of an IoC by hand.
- Keep an eye on the center of a power series: put the terms $(x-a)^k$ in
the formula; use a good center when using a power series to approximate
something.
- How to use the Squeeze Theorem.
- How to use all the tests for convergence of a series.
- How to compute the RoC and IoC of a given power series.
- How to compute the power series of a function and the function represented
by a power series.
- How to use power series in applications, such as:
- approximating functions or specific real numbers
- solving differential equations
- finding limits
Memorize:
- the power series for $e^x$, $\sin(x)$, $\cos(x)$, and the geometric
series (so the function is $\frac{1}{1-x}$) [I will put on the test
any other complicated power series you might need beyond those four.]
- the "absolute convergence implies regular convergence" theorem
- things about $p$-series
- the harmonic series and alternating version
- the divergence test
The Test Will Have:
- A summary of the table on page 673 of the book (without the lines on
geometric series, the divergence test, $p$-series, and absolute
convergence). So you don't need to memorize that table.
- There will definitely be problems along the lines of:
calculate the interval of convergence of a particular power series
- prove from the formal definition that a sequence limit has a certain
value
- some applications of power series, maybe a differential equation,
maybe a limit, maybe some approximation
- lots of series to apply all the convergence tests to
- maybe a squeeze theorem application