ln and e^x on the 16C?

[Gerson W. Barbosa]

(01-29-2018 12:47 PM)Mike (Stgt) Wrote:  Do not try to show your profound math knowledge on an HP-12C, that exp(n*ln(10)) is 10^n. Of course it is, but try with n=7.
10
LN
7
*
e^X
et voila!

What is wrong with 9999999.990? The absolute error might look high, but the relative error is very low. If 6.999999998 is acceptable for 1/(1/7) on all 10-digit HP calculators then that and all your other results surely are as well.

Incidentally that’s exactly the same example I’d already tried on the HP-16C yesterday, having stored ln(10) to full accuracy in register 9. I have to say I was pleased with the result ( 7 RCL 9 * GSB B -> 9 999 939.859 ). I was pleased even with my previous result ( 10 GSB A 7 * GSB B -> 9 999 776.098 ). BTW, I don’t claim a math knowledge beyond a skin-deep level (I wish I had been a braver math student, though).

Regards,

Gerson.