Re: Should I also buy a Ti89? Message #3 Posted by Eric Smith on 31 Oct 2007, 4:38 a.m., in response to message #1 by PhysicsNerd
If you're referring to the SAT Reasoning Test, I took it three weeks ago. (About 25 years late, but that's another story.) I took an HP 49g+ to the test, but there were no problems for which I needed to do anything beyond basic arithmetic on it. I could have gotten by fine with pencil and paper, but then I might not have had time to both doublecheck all my answers and twiddle my thumbs for several minutes.
I did not take the SAT Subject Tests in Mathematics. From the test descriptions, it sounds like any scientific calculator should be adequate. You're not going to be asked to evaluate triple integrals or compute eigenvectors; there aren't any particular special functions of either the TI89 or HP 50g that will give you a big edge.
If you're doing well in AP Calculus and have a little knowledge of basic statistics and probability, you should do fine on the math sections of the SAT Reasoning Test and on both of the SAT Subject Tests in mathematics. (And, for that matter, the quantitative part of the GRE, which I took this past August.)
Two years ago I took a linear algebra class for which the TI85 or TI86 were recommended. I was prepared to buy one if it proved necessary, but found that my HP 49g+ was more than adequate. The only drawback to not having the recommended calculator was that the professor would not have been able to show me how to solve problems on it, but I was able to work them all out myself without difficulty. Since the point of the class is to learn the math, not to learn the calculator, I'd claim that it doesn't make any difference which one you use, as long as you learn how to use it. So I wouldn't spend any money on buying yet another calculator of any sort, unless you decide that you're not satisfied with the TI84+ and HP 50g. (Or unless you just want another cool toy.)
My personal opinion is that any of the 48/49/50 series of calculators are fantastic for math, science, and engineering, and that I would have a harder time with the TI89. I bought a TI92 some years back, and IIRC the TI89 is basically a subset of that. I didn't find it to be nearly as convenient to solve calculus problems as the HPs. That may be due to my years of experience with RPL, ever since getting an HP28C back in 1987.
The main advice I would give anyone taking the SAT Reasoning Test has nothing to do with the math portion. Rather, I'd make a suggestion about the essay. They give you a topic and only 25 minutes to write on it. DON'T do what I did. I spent about five minutes organizing my thoughts and selecting three main points to write about. Then I wrote an introduction and thesis statement, and paragraphs about two of my main points. Time was called before I could write about my third point and a conclusion.
While I followed the correct process for writing a good essay, it's completely wrong for the SAT! I only scored 8 of 12 points for it, which dragged my overall writing score down considerably. I've since seen that Dr. Les Perelman of M.I.T. has studied SAT essays and found a near perfect correlation between essay length and SAT score, without regard to any normal quality metrics for the essay: http://www.nytimes.com/2005/05/04/education/04education.html. This indicates that you should spend no time thinking, and all 25 minutes writing anything that pops into your head. Fill that paper up!
By comparison, I scored 5.5 out of 6 on the essays for the GRE, a test which has higher standards.
