Sharp EL-W516X Calculation Examples Manual

[supernumero]

(03-04-2014 01:49 AM)Matt Agajanian Wrote:  Happy to announce that my new baby arrived today!! And with it came an exhuberant joy at how glorious it looks and how impressed I am with its design. It looks and feels as if it were designed with a professional appearance much like our HPs did in the days of Classic lineage.

I got an EL-W516X a few months ago. Unfortunately, I found what I deem an unacceptably low precision computing a natural log:

Correct value to 9 significant figures:
ln(0.9999995) = -5.00000125E-7

EL-W516X:
ln(0.9999995) = -5.00000075E-7

Absolute error: 5E-14
Relative error: 1E-7

So, only 7 significant figures of the answer given by the calculator are correct---a loss of 3 significant figures!

(I cannot remember the source for this test. IIRC, some vintage scientific calculators gave the wrong answer -5E-7, which is correct to only 6 significant figures. The current results are only marginally better.)

I also have a Sharp EL-506X, which gives the same wrong answer, but none of several other calculators (from different manufacturers) that I tested gave a wrong answer.

I liked the EL-W516X quite fine until I decided I didn't trust it in view of the above...

S.Numero