Integration

04032014, 01:50 PM
Post: #1




Integration
I ran across this simple definite integral recently
int(x,x,0,3) and the Prime hangs. I tried other limits and no problems. 

04032014, 02:17 PM
Post: #2




RE: Integration
I just tried your simple, definite integral int(x,x,0,3), with emulator in cas view;
in this case, the only thing hung was a nine over a two. 

04032014, 05:01 PM
Post: #3




RE: Integration
I'm using the physical Prime.
I tried the emulator as well, and if you pay close attention, you will notice a certain lag with this problem. Subsitute other limits, and the response is instantaneous. Go figure. 

04032014, 05:41 PM
Post: #4




RE: Integration
(04032014 05:01 PM)Helge Gabert Wrote: I'm using the physical Prime. Using the physical Prime. If you uncheck the Exact flag in CAS, you get the message: Adaptive method failure, will try with Romberg, last approximation was 4.5 If you leave the flag set and hit "On" after starting the calculation you get 9/2 instantly. In Home if you use the Template and input the integral, the calc hangs and pressing On results in Error: Invalid input, but only if the CAS a Exact flag is set. With the flag clear you get 4.5. Very strange Cheers, Terje 

04042014, 01:31 AM
Post: #5




RE: Integration
It doesn't really "hang".
It takes its sweet time, during which there's an animated hourglass in the top right corner of the screen, indicating activity. After a while, it spits out 9/2. While on the subject, is there a way to interrupt/cancel a calculation? 

04042014, 01:38 AM
Post: #6




RE: Integration
Yes, cancel with Esc or ON. Or ONSymb if ESC or ON don't work.
By the way, the above integral can be computed immediately by hitting the ON key, after pressing ENTER. 

04052014, 04:11 AM
Post: #7




RE: Integration
(04042014 01:38 AM)Helge Gabert Wrote: By the way, the above integral can be computed immediately by hitting the ON key, after pressing ENTER. Now *that* is truly bizarre. So it gets the result immediately, but... Decides to pretend it's taking longer? Quote:James T. Kirk: Mr. Scott. Have you always multiplied your repair estimates by a factor of four? 

04052014, 05:49 PM
Post: #8




RE: Integration
Yes, bizarre is the word.
Also, why would other integration limits not present any lag time problems, e.g., int(x,x,3,0) or int(x,x,0,5) are fine, only integrating x dx between 0 and 3 exhibits this behavior? 

04162014, 03:55 PM
Post: #9




RE: Integration
FWIW, further analysis shows that this behavior is affected by an upper limit of the form 3*2^(n1), n=1,2,. . . , i.e., 3, 6, 12, 24, . . . , with a lower limit of 0.


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