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Retro Review: TI-68
07-23-2017, 03:32 PM
Post: #1
Retro Review: TI-68

Years: 1989 - 2002
Type: Scientific, Formula Programming
Memory: 440 bytes, in 55 8-bit registers
Operating System: Algebraic
Memory Registers: Up to three characters

Batteries: 1 CR2032


[Image: 2017-07-23%2BTI%2B68.jpg]

What I love about the TI-68 is how complex numbers are integrated in the operating system. There is no need to switch to a separate mode. Best of all, the TI-68 handles exponential, logarithmic, power, and trigonometric functions with complex numbers.

The simultaneous solver also allows for complex numbers. This is indeed rare, as not even most graphing calculators’ simultaneous solving apps allow for complex numbers as coefficients. (Note: The HP Prime’s simult command allows for complex numbers)

Complex numbers on the TI-68 are notated as such:

Rectangular: (x, y)
Polar: (r ∠ θ)

Part extraction of complex numbers works slightly different: real and imag extract the real and imaginary portions of the complex number, regardless of setting.

Choosing the Precision?

The TI-68 allows for two precision settings: 10 digits or 13 digits. The display uses 10 digits. I think this is a rarity, if not a completely unique feature, since calculators in general uses an accuracy of 13 to 15 digits automatically.

I tested a couple of integrals and the precision setting does not affect the length of time either way. Both integrals were calculated in about 3 seconds.

Test Integral 1: ∫ (T^3 * e^(-T) dT, 0, 100, intervals = 6)
Test Integral 2: ∫ (X^2/(X^2 + X – 1) dX, 25, 75, intervals = 12)
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