Originally Posted by mitkw
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Thanks for all of the responses I appreciate it.
As to the TI-89 what is the main difference from the 84/83?
Also I have TI-92 which I bought and then found out could not use on standardized tests. How does it relate?
One more question. Several have mentioned RPN. While I know that it works in stacks rather than brackets, how would y'all say that it compares to AOS input? And are there RPN graphing calculators?
Thanks again. I'm still kind of new to all this.
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I'm an engineer. I work with scientific calculators all the time.
Since I was very young, I always had AOS calculators (TI-58C, TI-59) until I went to college. There, I worked in the campus bookstore and sold the things. I learned a lot there about the different kinds of calculators and input methods.
HP calculators and RPN, while you have to learn how to use them, are HEAD AND SHOULDERS above ANY AOS calculator.
It takes about 10 minutes to learn how to use one-- and when I worked in the bookstore I told people that 1) I would teach them, right there, how to use their new calculator, in 10 minutes or less and that 2) they could always come back again if they needed help and 3) if they were unhappy after learning how, they could bring back the calculator for a FULL REFUND. (we didn't give refunds on *anything* but I would somehow work it out for them if I needed to.)
In 4 years, I *never*, and I mean *never* had a single person bring back an RPN calculator. I also had many people *thank* me for teaching them how to use it.
Here is an example I would use: (20-3)/(2+5(pi)) = ?
(I would use trig or logs if they knew about them, but we'll keep this family-friendly for now)
On the AOS calculator, you type it in exactly as you see it, including parentheses. Sometimes, due to pending operations, it will do an intermediate calculation and sometimes not. For example, when you type the + after the 2, nothing happens, but when you type the close-parentheses after the 3 it calculates. This means you have to keep track of what you're doing, and you will type in 14-15 keystrokes. Don't forget the * between 5 and pi, also.
on the RPN calculator you type in both numbers and then hit the operation. You use the ENTER key to separate the numbers if necessary-- and if the number is already in the calculator, that's a bonus.
So you would type in: 20 ENTER 3 - 2 ENTER 5 pi * + /
and you have the answer in 12 keystrokes, and you always get an intermediate answer every time you hit an operation key.
If you don't get it, here's the explanation:
20 ENTER 3 are the first two numbers, we hit - to subtract them. 17 is now in the display.
2 ENTER 5 pushes the 17 down the stack, puts 2 on top of it, and puts 5 on top of that.
PI puts 3.1415927 on the stack, and * does 5*PI. 15.7080 is now in the display.
+ adds the 2 and the 15.7080 together to get 17.7080.
/ now divides 17 by 17.7080 and gives you the answer of 0.9600. QED.