Retro Review: TI-Explorer Plus

[Don Shepherd]

(12-17-2018 02:56 AM)Eddie W. Shore Wrote:  This should have been the modern TI-30X (adding the polar/rectangular and D/DMS conversions):

https://edspi31415.blogspot.com/2018/12/...lorer.html

Hi Eddie, nice review.

I used to use the OP1 and OP2 features of my TI-34 II here when I was teaching the famous quadratic formula to my students. I would ask them to think of two numbers, and give me the sum and product of the numbers. I could then tell them their two numbers by "magic". It turns out that X+Y = n1 and X*Y = n2 easily turns into an equation in the form ax^2 + bx + c, which is easily and quickly solved by the quadratic formula.

op1 = (-b+sqrt(b^2-4ac))/(2a)
op2 = (-b-sqrt(b^2-4ac))/(2a)

I would just set variable a=1, b=-the sum of the two numbers, and c=the product of the two numbers, press OP1 and OP2 and tell them their original numbers. They thought that was pretty cool, and it made it easier to teach the formula.

The calculator you have pictured doesn't seem to have variables, however.