       Re: if using Mathematica to solve an algebraic problem

• To: mathgroup at smc.vnet.net
• Subject: [mg109032] Re: if using Mathematica to solve an algebraic problem
• From: "David Park" <djmpark at comcast.net>
• Date: Sun, 11 Apr 2010 04:30:53 -0400 (EDT)

```Wow, a teacher who can teach and students who can think, and Mathematica
just integrated in as an aid for doing mathematics. Things are looking up.

David Park
djmpark at comcast.net
http://home.comcast.net/~djmpark/

From: Helen Read [mailto:hpr at together.net]

On 4/9/2010 3:32 AM, David Park wrote:
> Sometimes I find it difficult to understand these discussions.
>

I don't get this either. I teach my students to use Mathematica as part
of a mathematics course -- mainly calculus, but other classes as well.
We use Mathematica differently and for different purposes depending on
the subject matter. Using Mathematica does not subtract anything from
their learning of the course content. Rather, it adds to it.

As just one example, when we come to the topic of series in Calculus II,
after a little chalk (well, whiteboard) and talk, I give the students
some examples of series and have them make tables and plots of terms and
partial sums in Mathematica, and try to guess whether the series
converges (and if so, to what). I'll give them the following examples to
work on.

(a) A series that converges very quickly and obviously. (Usually I'll
use a geometric series for this, and I'll remind them of this example
example later on when we discuss geometric series.)

(b) A series whose terms don't converge to 0 (and thus the series diverges).

(c) The Harmonic series.

They go through (a) and (b) pretty quickly. When they get to (c), they
have a hard time deciding if the series converges or diverges. They will
puzzle over it for quite a while. Some of them will make tables and
plots of partial sums going out to thousands of terms in the series, and
still they are unsure if the series converges or diverges.

After letting them work while I walk around and answer questions, we
stop to discuss the examples. The class will tell me that Example (a)
has terms that converge to 0, and the partial sums converge to (whatever
I have rigged it to). For (b), they will explain that the terms converge
to let's say 1/2, and so the partial sums increase approximately
linearly with a slope of 1/2, and the series diverges. From this, they
make the observation that if a series has terms that do not converge to
0, there is no way the series could converge.

Then we get to (c). The terms converge to 0, and it's tough to tell
whether the partial sums converge or diverge, but most of them will lean
toward thinking that they diverge. So then I lower the boom. Let's
*prove* that it diverges. This leads us into a discussion of the
Integral Test. We continue with this interplay between concrete examples
in Mathematica and analytical work on the board as we progress through
the chapter.

I don't understand how anyone would think that this use of Mathematica
is "dangerous" or "threatening" or somehow prevents my students from
learning the subject. On the contrary, this use of Mathematica helps my
students to gain some conceptual understanding of a topic that they
otherwise find difficult and abstract.

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