Bug: solve(), nsolve() and fsolve() depend on angle mode?
02-14-2014, 07:23 PM (This post was last modified: 02-14-2014 08:14 PM by CR Haeger.)
Post: #1
 CR Haeger Member Posts: 275 Joined: Dec 2013
Bug: solve(), nsolve() and fsolve() depend on angle mode?
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
02-15-2014, 12:41 PM
Post: #2
 Tugdual Senior Member Posts: 754 Joined: Dec 2013
RE: Bug: solve(), nsolve() and fsolve() depend on angle mode?
- 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.
02-15-2014, 01:44 PM
Post: #3
 CR Haeger Member Posts: 275 Joined: Dec 2013
RE: Bug: solve(), nsolve() and fsolve() depend on angle mode?
(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.
02-15-2014, 02:13 PM
Post: #4
 Miguel Toro Junior Member Posts: 49 Joined: Dec 2013
RE: Bug: solve(), nsolve() and fsolve() depend on angle mode?
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
02-15-2014, 03:12 PM
Post: #5
 CR Haeger Member Posts: 275 Joined: Dec 2013
RE: Bug: solve(), nsolve() and fsolve() depend on angle mode?
(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.
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