Hp 39gii integration fail

05122014, 03:00 AM
Post: #1




Hp 39gii integration fail
The function 3*x^(2/3)2*x graphs fine, d/dx set to zero in solve app finds extremum at (1,1).
When integrating, regardless if I use x^(2/3) or 3 root x fails. In the plot, area under curve from 0 to 3.375 yield an answer ~.08+ vs? real answer of ~2.28. Is this a bug? 

05122014, 03:41 AM
Post: #2




RE: Hp 39gii integration fail
Side note...same function integrates fine away from 0.
Integrating 3*x^(2/3)2*x from 1 to 2 gives correct .91464378706 11 digit answer in ~5 seconds. Integrating same function written as 3*(3 root x)^22*x gives same answer in ~21 seconds. Taking area under curve in plot app from 1 to 2 gives same correct 11 digit answer almost instantaneously! 

05122014, 04:50 AM
(This post was last modified: 05122014 04:51 AM by kakima.)
Post: #3




RE: Hp 39gii integration fail
I'm not quite duplicating your results.
On the home screen, integrating from 0 to 3.375 my 39gII gives me the ~2.28. In the function app, the signed area from 0 to 3.375 gives me "Undefined." Going from 0.001 to 3.375 gives me ~2.28. Edit: I do get your results integrating from 1 to 2. 

« Next Oldest  Next Newest »

User(s) browsing this thread: 1 Guest(s)