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+--- Thread: Bug: solve(), nsolve() and fsolve() depend on angle mode? (/thread-678.html)
Bug: solve(), nsolve() and fsolve() depend on angle mode? - CR Haeger - 02-14-2014 07:23 PM
Hello,
On handheld or emulator, In CAS mode solve(), nsolve(), fsolve() appear to work correctly in either angle mode. However in HOME mode:
- fsolve(X^2-5,X) yields [[]] when in degrees mode. Same for CAS.solve(), CAS.nsolve()
- fsolve(X^2-5,X) yields [-2.24 2.24] when in radians mode. Same for CAS.solve(), CAS.nsolve()
I searched here but did not see this issue posted.
Best,
Carl
RE: Bug: solve(), nsolve() and fsolve() depend on angle mode? - Tugdual - 02-15-2014 12:41 PM
Two comments:
- variable definitions are x in CAS and X in Home (even if you tell on which variable you solve, I know this is weird)
- most of the solve functions require an expression with '=' sign. In the best case you'll get a warning telling you that it assumes "=0" otherwise you just don't know what happens
Now, I played with your example and didn't find a connection with use of degrees/radians but the solve functions are extremely chaotic for sure and the help quite inexistant.
RE: Bug: solve(), nsolve() and fsolve() depend on angle mode? - CR Haeger - 02-15-2014 01:44 PM
(02-15-2014 12:41 PM)Tugdual Wrote: Two comments:
- variable definitions are x in CAS and X in Home (even if you tell on which variable you solve, I know this is weird)
- most of the solve functions require an expression with '=' sign. In the best case you'll get a warning telling you that it assumes "=0" otherwise you just don't know what happens
Now, I played with your example and didn't find a connection with use of degrees/radians but the solve functions are extremely chaotic for sure and the help quite inexistant.
Thanks for your comments and looking at this. Yep, I know about x vs X as CAS vs Home variables. It also seems that you don't always need the "=" sign in the expression. As others have posted - I wish there were a "help popup or tool-tip" that was available when selecting these functions...
I'm still seeing these errors in HOME depending on degree/radians settings. I hope this gets looked at as it can be convenient to run these solve functions from HOME - but less so if I have to check to be in radians mode.
RE: Bug: solve(), nsolve() and fsolve() depend on angle mode? - Miguel Toro - 02-15-2014 02:13 PM
Hi,
Until this is solved, in HOME mode, you could always use the CAS("fsolve(x^2-5,x)") syntax. It will work either with degrees or radians modes.
Regards,
Miguel
RE: Bug: solve(), nsolve() and fsolve() depend on angle mode? - CR Haeger - 02-15-2014 03:12 PM
(02-15-2014 02:13 PM)Miguel Toro Wrote: Hi,
Until this is solved, in HOME mode, you could always use the CAS("fsolve(x^2-5,x)") syntax. It will work either with degrees or radians modes.
Regards,
Miguel
Thank you Miguel -I see that the format you suggested is more robust. I guess just calling fsolve() from the toolbox>Catlg and using X vs x while in HOME is not as robust.