Crash when Solve for Integral with 15C

[Dieter]

(09-06-2017 12:10 PM)Joe Horn Wrote:  

(09-06-2017 11:15 AM)Gamo Wrote:  ...
The answer should be 0.03662

Wolfram Alpha's result agrees with Prime: the answer is exactly 2-ɣ-log(4) which is ≈ 0.03648997397857652....

FTR: The WP34s integration routine seems to perform better here:

FIX 5:  ∫ ≈ 0,03649
ALL 3:  ∫ ≈ 0,03648997398363982

The latter is at least correct in all displayed digits. ;-)

(09-06-2017 12:29 PM)Gerson W. Barbosa Wrote:  More about this integral at ...

Ah, now I know why this integral looked so familiar! It was mentioned in the HP-Journal article on the then-new 34C and its integrate function (which seems to be more or less the same in the 15C). The indeed wrong answer in FIX 5 mode is explained there, just as the correct result 0,0364900 in FIX 7 mode: "The answers are wrong but the calculator is right". ;-) Again, the error is caused by problems with the numeric evaluation of the integrand which has an very sharp spike near x=0, and it is shown how this can be avoided and the correct result can be obtained.

Dieter