Mathochism: Shame shame shame

One woman’s attempt to revisit the math that plagued her in school. But can determination make up for 25 years of math neglect?

We got our tests back today. I had been crossing my fingers for a high C, since I knew I had messed up on at least two problems, and hoped to get partial credit on a third. When you only have 10 problems total, the margin for error is slim.

But I got an F.

Well, that was unexpected! In fact, it’s quite a shock. I’m still processing this failure, but at least we went over the exam in class.

In one of the problems I unexpectedly got wrong, I ironically had the right answer.

The problem was to find the limit of √(x-3)²/x-3 as x goes to 3. I immediately recognized that as a limit that can’t exist, because there are two pieces that each have different limit. I tried to
explain, but still got it wrong, and the reason my explanation didn’t pass muster is because I should have recognized √(x-3)² is absolute value of x-3 in disguise.

Even without doing that, though, the answer is still DNE because there is no way to tweak this to fill the hole at 3. It’s not a couch, it’s the Grand Canyon. Oh well. So much for that.

On another problem, I mixed up the technique for finding limits with the technique for defining continuity. I should have multiplied the polynomial by its conjugate, turned it into a rational function, and gone to town. Ironically, again, I recognized the right technique on the next problem, and got that right. I failed to see through the previous problem’s disguise. In my defense, the homework focused heavily on rational functions. I would have gotten a lot more practice if there had been a mixture of polynomials and rational functions.

Oh well. Another reason this book continues to disappoint me.

I got both problems I knew I got wrong wrong, so that left 60 points to play with. As expected, I only got partial credit on that one piecewise problem. And I got a point off for a misplaced negative here, an interval bracket there. I had figured in such issues in my C projection. Again, with 10 questions, there is a slim margin for error.

But screwing up those other problems? Yeah, that was a shock. Happily, I can drop this test. I wish I could do the same with the shame. I really do understand this stuff — why do I keep missing the traps?

All text copyrighted by A.K. Whitney, and cannot be used without permission.