The TI-89 was able to perform symbolic differentiation and integration as well as first and second order differential equations. It didn’t show the steps though.
Did the TI-92 Plus show the steps to get to the answer or did it just show the answer in symbolic form?
I gather that I’m a few years older than you and I know that there were features added in future releases which were not in the original release. Maybe that was one of the releases?
The other graphing calculator I have is the TI-86 which will give approximate integration values if an upper and lower bound are specified, but it’s bedieved.