The Logic Behind Pre AOS TI Calcs

[Matt Agajanian]

Hello all.

As I remember from browsing the brochures for TI's SR-50 and 51 (thanks Joerg Woerner), it was mentioned at the last pages of the brochures that TI had a choice between algebraic and RPN entry (which featured a somewhat inaccurate representation of RPN's method to solving the example). But, alas, and here's a lead in to the point of my curiosity, neither the original SR-50, SR-51, nor their A versions featured parentheses but, incorporated an x<>y exchange mechanism. More to the point, in the manuals for these four calcs, the keystroke sequences for the more advanced calculation examples were far from straightforward entry methods.

So, my question or questions are in what ways were TI's entry methods for the SR-50, 51, 50A, 51A natural and easier (or even easier than RPN, for that matter)?