WP 34S integration accuracy

[ijabbott]

I saw a video comparing integration speed of two Casio calculators - an fx-991DE X "CLASSWIZ" (German version of the fx-991EX) and an old fx-991ES (similar to an fx-115ES, and older than the "PLUS" models).

The integral used was an "improper" definite integral between -5 and 99 of "ln(x²).dx". It contains a singularity at x=0. The fx-991DE X completed it in about 36 seconds and gave a pretty accurate numeric result. (The exact answer according to my HP 50g is "99*LN(9801)+10*LN(5)-208", which is 717.9281095 to 10 significant figures, and this is the answer shown by the fx-991DE X.)

Of course, I wanted to see how the WP 34s compared, so I entered the function:

Code:

001 LBL'I'
002 x²
003 LN
004 RTN

and integrated it between -5 and 99 with the display in 'ALL' mode. The integration ran for about 31 minutes and produced the final answer 717.934270433, which is accurate to about 5 digits. The PC emulator is a lot faster but produced the same answer.

For comparison, a HP 50g with the CAS mode set to 'Approx' took 26 minutes and produced the answer 717.928325369. A HP 35s could only perform the integral if the display was set to 5 digits or less and took 59 seconds to produce the answer 7.18002e2 (in 'SCI 5' mode). A TI 36X Pro took about a minute and produced the answer 717.9281268 which is accurate to about 7 digits.

I'm guessing it's the improper nature of the definite integral which is throwing things out of whack. Still, an interesting comparison, I think.