Texas Instruments TI-89

Datasheet legend
Ab/c: Fractions calculation
AC: Alternating current
BaseN: Number base calculations
Card: Magnetic card storage
Cmem: Continuous memory
Cond: Conditional execution
Const: Scientific constants
Cplx: Complex number arithmetic
DC: Direct current
Eqlib: Equation library
Exp: Exponential/logarithmic functions
Fin: Financial functions
Grph: Graphing capability
Hyp: Hyperbolic functions
Ind: Indirect addressing
Intg: Numerical integration
Jump: Unconditional jump (GOTO)
Lbl: Program labels
LCD: Liquid Crystal Display
LED: Light-Emitting Diode
Li-ion: Lithium-ion rechargeable battery
Lreg: Linear regression (2-variable statistics)
mA: Milliamperes of current
Mtrx: Matrix support
NiCd: Nickel-Cadmium rechargeable battery
NiMH: Nickel-metal-hydrite rechargeable battery
Prnt: Printer
RTC: Real-time clock
Sdev: Standard deviation (1-variable statistics)
Solv: Equation solver
Subr: Subroutine call capability
Symb: Symbolic computing
Tape: Magnetic tape storage
Trig: Trigonometric functions
Units: Unit conversions
VAC: Volts AC
VDC: Volts DC
Years of production:   Display type: Graphical display  
New price:   Display color: Black  
    Display technology: Liquid crystal display 
Size: 6"×3½"×½" Display size:  pixels
Weight: 10 oz    
    Entry method: Formula entry 
Batteries: 4×"AAA" alkaline + 1×"CR-1616" Lithium Advanced functions: Trig Exp Hyp Lreg Grph Solv Intg Ab/c Cplx Symb Cmem Mtrx 
External power:   Memory functions:  
I/O: TI-GraphLink™     
    Programming model: Formula programming 
Precision: 14 digits Program functions: Jump Cond Subr Lbl Ind  
Memories: 192(0) kilobytes Program display: Formula display  
Program memory: 192 kilobytes and 702 kilobytes Program editing: Formula entry  
Chipset:   Forensic result: 8.9999999817692  

ti89.jpg (29508 bytes)The TI-89 is probably the best calculator ever made by Texas Instruments. In fact, this machine is living proof that the good old rivalry between the world's two premier calculator manufacturers, Hewlett-Packard and Texas Instruments, is still alive and well.

This handheld calculating instrument has just about everything you could ask for in a calculator. A huge amount of memory, even more memory for archiving objects, flash-upgradeable operating system software, a symbolic algebra system, a high-resolution, high-contrast LCD display, just to name a few of its outstanding features.

The TI-89 is actually a close relative of the TI-92. The capabilities of the two machine are nearly identical, except that the geometry application that's a standard feature of the TI-92 is available only as an optional download for the TI-89.

For most calculators, I use a classic computational problem, that of the Gamma function, as a demonstration of the machine's programming capabilities. The TI-89, however, deserves more; it belongs to that exclusive club of calculators on which user-defined functions can take advanced object types, such as algebraic expressions as parameters. (Other members of this club include the HP-28C and HP-28S, the HP-48S/SX/G/G+/GX, the HP-49G, and of course the TI-92 and TI-92Plus.) One very interesting, and practical programming example (used frequently by surveyors, I am told) for such calculators is computing the radius of curvature for an arbitrary function. For any function f(x), the radius of curvature at any x=x0 can be obtained by evaluating (1+(f'(x)2))3/2/f''(x). The function below, named roc, can be invoked for instance as follows: roc(x^2,x,0). This will calculate the radius of curvature of a the parabola y=x2 at x=0.

:Return ((d(f,z))^2+1)^(3/2)/(d(d(f,z),z))|z=z0