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Integration and derivation commands on HP-49g+ - Antonio Maschio (Italy) - 01-10-2007 I'm a bit confused about the derivation and integration capabilities of the CAS system with respect to indefinite math.
Please, can anyone confirm the following? (Of course these should work only with non approx flags set.) for integration with respect to the X variable, use INTVXAm I right? Is there any other way? Thanks in advance. -- Antonio
Re: Integration and derivation commands on HP-49g+ - Norris - 01-10-2007 I have a 50G, but it should be similar to a 49G+. The INTVX and DERVX commands (and other "VX" commands, such as SOLVEVX and SIGMAVX), use whatever independent variable is stored in {HOME CASDIR VX}. The default value for VX is "X", but you can change this to "Y" or "t" or any other variable, by adjusting the "Indep var" setting in MODE CAS. For example:
If you have X in VX, then INTVX(8) returns 8X Since the VX commands automatically use whatever independent variable in VX, you don't need to specify the independent variable. Alternatively, you can use DERIV instead of DERVX, or RISCH instead of INTVX. However, these commands ignore VX, and expect you to specify the independent variable. For example:
RISCH(8,X) returns 8X DERIV and RISCH might be preferable if you were working with several different independent variables. Suppose, for example, that you were taking partial derivatives of functions with respect to X, Y, and Z. If you used DERVX, you would have to keep resetting the variable in VX. It would probably be easier to use DERIV instead. The term "RISCH" presumably refers to the Risch algorithm for finding antiderivatives
Edited: 10 Jan 2007, 4:42 p.m.
Re: Integration and derivation commands on HP-49g+ - Hal Bitton in Boise - 01-10-2007 Thank you Norris... Re: Integration and derivation commands on HP-49g+ - Norris - 01-10-2007 Sorry, I have no plans to rewrite the HP50G User's Guide. However, I do agree that it could be improved. I wonder if perhaps the "Wikipedia" approach could generate some good free documentation for the 50G. There might not be anyone out there who wants to write a whole manual, but there might be lots of people in the HP community who would be willing to describe and review one feature at a time. Who knows, you might generate a User's Manual that was actually written by users.
Edited: 10 Jan 2007, 8:00 p.m.
Re: Integration and derivation commands on HP-49g+ - RON ALLEN - 01-10-2007 Nice job on integration. Wasn't asked or answered - as a part of efficiencies offered by the cas VX approach - I find it much easier To use the X variable when I can because of the assumption by cas of x also makes use of the x key in the 50 assumed alphabetic. This to me represents nearly half of the time gained, i.e. having the x key always shifted to alphabetic for the primary variable of integration, especially if you repeat that variable more than once plus dX. Ron PS That user-friendly feature was not on my 49 g+, only my 50. Regards,
Ron
Re: Integration and derivation commands on HP-49g+ - Antonio Maschio (Italy) - 01-11-2007 Thank you, Norris, very precise and helpful.
-- Antonio
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