In my college days I had a Casio calculator. You enterred equations in a format that was very much like the BASIC language. The really slick feature was the Back Arrow key that would bring up the last equation enterred so you could edit it and hit exe for the next answer.
Encouraged you to learn how to manipulate your equation so the variable that needed to be changed was at the end so it was easy to backspace a couple times, change the number and get teh next answer to fill in the table.
Plar to rectangular and rectangular to polar were a snap.
Unfortuantely, because of tight household budget, my wife used it when shopping and thedisplay didn't survive her purse. Have aleays wanted one like it but have never found another...
RBedell, I agree. The calculator still has a place in today's smartphone, tablet society. I use "Real Calculator" on my DroidX and Internet Tablet but the TI89+ graphics calculator has a really cool interface for Arduino controls projects. I also agree the embedded menus to obtain math functions on the TI89+ kind off discourages you to use it because of the added access time. But like most engineers, I'll never give it up because it represents an era of learning engineering, mathematics, and solutions in the palm of your hand.
I once found a TI calculator in a drawer in a lecture hall at the university where I work. It was a graphing calculator and it looked like someone had used a magnifying glass and burnt dimples in the display. This thing had been in the lecture hall for sometime collecting dust so I had no problem taking it. There were enough dimples to make seeing the display unpleasant. I tried to fix it...right. I got to the display and started peeling up the plastic on the surface. That was when I started understanding how the display is assembled. The plastic polarizer had the dimples. When that got removed, the info on the display could not be seen anymore. Then I got an idea. I use polarized sunglasses, so I put them on. Vola! I could read the display but without the glasses the display was blank. It also meant the the calculator had to be orientated right in order to see the display. Because I was going to school at the same time, this gave me some ideas which I never acted upon. After all, it was a TI calculator not an HP. I use an HP.