Retro Review: TI-Explorer Plus

[Eddie W. Shore]

This should have been the modern TI-30X (adding the polar/rectangular and D/DMS conversions):

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

[ijabbott]

What's the maximum number of digits in the denominator that can be displayed? I'm wondering how many digits of the display need that extra segment for the fraction slash.

[Eddie W. Shore]

(12-17-2018 02:26 PM)ijabbott Wrote:  What's the maximum number of digits in the denominator that can be displayed? I'm wondering how many digits of the display need that extra segment for the fraction slash.

I think it's 4.

[ijabbott]

(12-17-2018 02:55 PM)Eddie W. Shore Wrote:  

(12-17-2018 02:26 PM)ijabbott Wrote:  What's the maximum number of digits in the denominator that can be displayed? I'm wondering how many digits of the display need that extra segment for the fraction slash.

I think it's 4.

It appears the slash doesn't have to appear before the 4 rightmost digits of the display. The picture of the TI-40 Solar (China) on datamath.org shows the calculator showing a mixed fraction with the number starting on the left and the slash somewhere left of the middle.

[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.

[Eddie W. Shore]

(12-18-2018 03:54 PM)Don Shepherd Wrote:  

(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.

Right, both the TI-40 and TI-Explorer Plus have only one memory register. Excellent use of OP1 and OP2.