88883888.
This is how much my calculator loves me. Just yesterday, it loved me five thousand more. Alas, old age, weathering, and living at the bottom of my backpack have taken their toll.
Two stinkin'
picture elements are dead. That's twice as many as all it takes to render the
display next to useless. It's still usable, but...
it's not the same.
A TI-89 is highly recommended for this class.
I've had this calculator for the better part of this past decade. It has served me well through middle school "math", geometry, algebra, and trigonometry, and has turned the sun into productive math.
A calculator that does calculus will be useful on the AP exam.
I don't know how I'll get by without it. It's like losing an old friend. It's like wearing shoes that don't fit. It's like...
Hmm. eBay has a used one for $7, and a brand spankin' new one for $10. What if...
LCD screens passing away after many years notwithstanding, the TI-25X SOLAR is the best calculator I have ever used. It's really small, the buttons are arranged in a logical manner, and it doesn't need any batteries. It has all the features of any larger scientific calculator, but its advantages are that it's smaller and much simpler.
Features:
Texas Instruments sadly discontinued this model sometime after the year 2000.
Download the manual: http://education.ti.com/us/product/tech/25x/guide/guides.html
Datamath calculator museum: http://www.datamath.org/Sci/Modern/TI-25X_SOLAR.htm