Monday, February 14, 2011


At the end of class today I asked my Calc II students to write Twitter-style tweets in which they describe how to use the method of integration by parts. To help them stay within the 140-character limit of the genre, I provided them with graph paper on which I'd blocked out boxes containing 140 squares apiece.

The results?

They found it hard to say all that they wanted to say, so they had to focus on the issues most central to the method. (This, of course, was the point of the exercise.) Some tried to save space by eliminating spaces between words or by eliminating vowels. The former resulted in text that was still readable; the latter, I would argue, did not. Compare:



"Use da frmla fr ibp's. you cn chse ne prt fr u. da othr prts r dv. slve fr du and v. thn plg into frml. look a pngun <(") !!!!11one!!!"

Not only is the first easier to read; it's also correct, complete, and doesn't succumb to silly non sequitur by the end.

Some of the best were short and to the point, and even managed to get in some guidance about how to choose u and dv: "Sudv=uv-SvduumustgetsimpledvmustbeS.use formula above solve" was far terser than it needed to be; throw in a few spaces to make it more readable, and expand on what "mustbeS" surely means:

"Sudv=uv-Svdu. u must get simple. dv must be integrable. use formula above. solve."

is still well within the 140-character limit.

Clearer, but not quite as complete (it makes no mention of dv), and still pretty solid:

"pick a portion of the original integral that will get simpler when derived and set it to u, then do int(f(x))=uv-int(vdu)."

Several others were nearly as good, but used slightly awkward notation or omitted critical pieces of the formula. From what I can tell, the students get the gist of the process, but may still be a little iffy on the details.

Practice, people, practice! This gets much easier after you've done a few of them. If you want to go over a few examples together, please come on by. I'd love to work on a few with you. You'll get there, I promise.

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