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Texas Instruments TI-30Xa Solar School Edition (Virgina 3rd edition 2013)

Date of introduction:  August 2013 Display technology:  LCD
New price:  $11.99 (SRP 2013) Display size:  10 + 2
Size:  6.0" x 3.0" x 0.6"
 153 x 76 x 15 mm³
   
Weight:  2.8 ounces, 78 grams Serial No:  
Batteries:  n.a. Date of manufacture:  mth 05 year 2013 (B)
AC-Adapter:   Origin of manufacture:  China (K)
Precision:  12 Integrated circuits:  
Memories:  3    
Program steps:   Courtesy of:  Joerg Woerner 

What a surprise! Fellow calculator collector John Kleperis informed us in October 2015 that Texas Instruments quietly introduced the third generation of the famous TI-30Xa Solar School Edition sporting the design of the TI-30Xa.

Dismantling this TI-30Xa Solar School Edition manufactured in May 2013 by Kinpo Electronics, Inc. in China reveals no surprises. The printed circuit board (PCB) of the calculators sports still a prominent SR-30S logo - with a revision index of 10. A TI-30XA calculator manufactured four years earlier by Kinpo Electronics, Inc. carried a SR-30-12 designator.

Technically this calculator is identical with the TI-30 ECO RS sold in Europe.

Since its introduction in 1996 we verify with each TI-30Xa the presence of the Logarithm Bug and - yes....

The algorithm problem known as "Logarithm Bug" was implemented already 1991 with the TI-35X and TI-36X SOLAR and floats around in various calculators.
The best way to demonstrate the logarithm bug could be found with the exponential function, one of the most important functions in mathematics. It is written as ex and can be defined as a limit of a sequence:

The calculation of this expression will yield to unexpected results due to:

The ln(1 + x) problem 
The way yx is calculated

Using n=109 should reveal a very close approximation of ex=2.71828183 (rounded to 9 digits) but this TI-30 ECO RS manufactured in 2013 still indicates 2.71919279.



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If you have additions to the above article please email: joerg@datamath.org.

© Joerg Woerner, December 25, 2015. No reprints without written permission.