Re: Alkaline batteris vs nickel cadmium Message #6 Posted by Ellis Easley on 26 Mar 2002, 3:35 a.m., in response to message #5 by aruid
The ones I have are the only ones I have seen, except I think a high school friend might have had a 2500 in the 70's! They all have the same battery cover except it goes on in the opposite direction on the 2550 vs. the others.
Here is an interesting difference: my 2500 display has LEDs that look like individual dots while my 2500II display has continuous segments. I have two 2550's and their displays are different as above. I guess this was a "running change" TI made.
First I got the 2500II by itself and later the 2500 with its booklet and was surprised to learn the "tricks" that TI described to extend the usefulness of the calculator, using the constant feature to reuse the first parameter as the second with "*" to square numbers or get higher integer powers; with "/", twice, to accomplish "1/x"; and finding square roots by repeatedly dividing by a guess, adding the guess, and dividing by 2 to get a closer estimate. That last one makes you appreciate the memory when it is available!
I had to read those tricks in the TI booklet, but when someone raised the issue of the changing accuracy (precision?) of "y^x" on HP calculators recently, I figured out how to do it on the 9100 on my own, reacquainting myself with the slide rule in the process  y^x=e^(ln(y)*x)  and this lets you find 10^x, since the 9100 only has ln(x), e^x, and log(x). I first looked in the Museum 9100 article for this "workaround" because I thought I had read it there, but if it is there, I missed it.
