Hp 39gii integration fail - Printable Version +- HP Forums ( https://www.hpmuseum.org/forum)+-- Forum: HP Calculators (and very old HP Computers) ( /forum-3.html)+--- Forum: General Forum ( /forum-4.html)+--- Thread: Hp 39gii integration fail ( /thread-1295.html) |

Hp 39gii integration fail - lrdheat - 05-12-2014 03:00 AM
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? RE: Hp 39gii integration fail - lrdheat - 05-12-2014 03:41 AM
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)^2-2*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! RE: Hp 39gii integration fail - kakima - 05-12-2014 04:50 AM
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. |