National Semiconductor 4515 Mathematician PR

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: Numeric display  
New price:   Display color: Red  
    Display technology: Light-emitting diode 
Size: 6"×3"×1" Display size: 8 digits
Weight: 6 oz    
    Entry method: Reverse Polish Notation 
Batteries: 3×"AA" NiCd Advanced functions: Trig Exp 
External power: NS adapter   Memory functions: +/- 
    Programming model: Keystroke entry 
Precision: 8 digits Program functions:  
Memories: 1 numbers Program display:  
Program memory: 102 program steps Program editing: Step delete capability  
Chipset: National Semiconductor   Forensic result: 8.843762  

ns4515.jpg (23818 bytes)When I first read about the Novus Mathematician PR, I began to wonder: what makes this calculator different from its close relative, the Novus Scientist PR? They seem to have nearly identical functionality, at least judging by their keyboards alone.

When I finally got my hands on one of these machines, I had my answer: imagine a calculator with a full complement of scientific functions that cannot display numbers in scientific notation! What the...

It is also an RPN calculator like the Scientist PR, but apparently, it only has a three-level stack, and no stack roll function. Sometimes it really makes me wonder, just what were these designers thinking!

There is one area in which the Mathematician PR is a little better than the Scientist PR: its mathematical algorithms are more accurate. For instance, 1 arc tan actually yields a result of 45, instead of 45.000654 like on the Scientist PR...

With this machine's crippled RPN model, the polynomial approximation of the Gamma function, my favorite programming example, is a no go. But an enhanced version of Stirling's formula can be written easily, yielding at least 5 digits of accuracy for arguments 2 and above. For instance, 5 start yields 24.00004, which is pretty darn close to the correct result, 24.