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Just got a TI89 for the May 3rd SAT. I heard it is much more powerful than the 83 plus I had previously been using, so I figured it would be a good investment. I have pretty much mastered the 83 functions, and was wondering what advantages the 89 will give me on the math section of the SAT.

For example, can you describe how I can use its features that the 83+ doesnt have which would be useful on the SAT. An example of how to solve a problem you wouldn't be able to on the 83+ would also be appreciated, if possible.

Thanks a lot guys, I appreciate the help!

By Dxiw (Dxiw) on Friday, March 14, 2003 - 04:29 pm: Edit

umm, quarky I'm too lazy you explain.
basically,
isPrime
solve
and a bunch of other stuff..lol

By Montydsw11 (Montydsw11) on Friday, March 14, 2003 - 05:47 pm: Edit

Um cool... some time when you are feeling less lazy could you elaborate a little more? lol

Thanks!

By Jumbo (Jumbo) on Friday, March 14, 2003 - 06:36 pm: Edit

TI89 won't help your math SAT score anymore than a TI83, nor even a simple 4 function calculator.

By Quarky (Quarky) on Friday, March 14, 2003 - 08:14 pm: Edit

Jumbo is not correct. Dxiw is -- he is too lazy, so I (Quarky) will explain.

One of the widely used functions of 89 that is helpful on the SAT is the solve() functions. Not only does it solve for simple one-var equations (e.g., solve(x^2-1=0,x)), but it also does multi-var simultaneous equations like (x+y=7 and y-x=3,x)
isPrime() is good for those weird prime number questions

factor() and expand() are useful sometimes.t

the 89 can also perform calculations in the exact mode, which returns exact values (fractions, square roots, etc) as opposed to decimal ones.


eh.. that's all i can think of right now.

By Satman04 (Satman04) on Monday, March 17, 2003 - 03:25 pm: Edit

ehh u didn't need to buy a whole new calculator for those functions...

All you needed to have done was download a few programs for the TI-83 plus; no big deal.

By 9331 (9331) on Monday, March 17, 2003 - 03:35 pm: Edit

the ti-89 is wonderful for calculus. It can do derivatives, antiderivatives, arc length, taylor sums, limits.....

By Quarky (Quarky) on Monday, March 17, 2003 - 06:15 pm: Edit

Exactly. It is not just the SAT one buys the 89 for. In fact, I can do as well with the 83 it doesnt matter. As long as I can graph fcns, it's perfect. The 89 is awesome for calc and programming, which I love

By Incognito (Incognito) on Monday, March 17, 2003 - 06:30 pm: Edit

bump

By Crammer (Crammer) on Monday, March 17, 2003 - 07:09 pm: Edit

The way I thought about it was solving for the values of the two columns. You can quickly tell that the first two expressions (s-r) and (t-s) are the ones that are going to help solve for column a because they are the the two that include t r and a common third variable.

From there you can go two ways. I didn't really solve it. I just looked at it for a few seconds before I realized that if you add the left side to the right side ((s-r) + (t-s) = (t-r)), you get the answer you were looking for. Basically, t-r = 2(s-r) = 2(t-s) = 2(m-t)....

Column B is much easier. Column B is simply the sum of two of the equivalent expressions ((w-v)=(t-s)). Therefore column B, (w-v) + (t-s) = 2(s-r) = 2(t-s) = 2(m-t).... Therefore the two columns should be equal and the answer is (C). I'm pretty sure thats correct but I dont have any answer key.

I'm not sure if there's a more algebraic way of solving this problem or if that's simply what you did. Either way, I think there's nothing wrong with that method.

By Incognito (Incognito) on Monday, March 17, 2003 - 07:23 pm: Edit

sorry about that, Crammer. I didnt think that anybody would respond. Let me repost the question so that others can see it. The following was supposed to be in my March 17, 2003 - 06:30 post:

To Quarky (or anyone else who may be good w/algebra) :

I found this SAT I math question a long time ago. I opened my book and found it circled in red. I was able to solve it and find the right answer pretty quickly (probably under 40 seconds) using the plug-in method only when I did it. However, I feel guilty using this method, because it requires little or no thinking. I have thought about it when I did it, but have not figured out the algebraic method of solving the problem (which is why it was circled in red). It is a quant comparison, and the last in its set. Here it is:

s-r = t-s = m-t = v-m = w-v

:::Column A::::
(t-r)

::::Column B::::
(w-v) + (t-s)

This question has been bothering me, mainly because I am usually really good at doing this stuff. What would be the algebraic method of solving the problem (I know that the plug-in method works, but I'd like to see if I'm missing something)?

By Incognito (Incognito) on Monday, March 17, 2003 - 07:27 pm: Edit

BTW, thanks for the response, Crammer. The answer is C.

By Dwaynehoover (Dwaynehoover) on Monday, March 17, 2003 - 11:54 pm: Edit

Yes there is nothing wrong with that method, just plug in for r to find that t-r is in fact = 2t-2s or 2(t-s) --- That seems like a rather difficult problem for the SAT I.