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- anonimnystefy
- 2012-10-27 10:29:54
That looks ok too.
- zetafunc.
- 2012-10-27 09:20:51
reconsideryouranswer wrote:
anonimnystefy wrote:
i was wondering what derivatives of |x| and sgn(x) are.
i thought of something but i got that they were sgn(x) and 0
respectfully.i think something is wrong here.What?
Sorry for the bump, but could you not just say
?
- anonimnystefy
- 2011-11-13 12:12:46
nice explanation! thanks rya!
i guess sgn(x) can be done similairly.
- reconsideryouranswer
- 2011-11-13 12:10:15
anonimnystefy wrote:
i was wondering what derivatives of |x| and sgn(x) are.
i thought of something but i got that they were sgn(x) and 0
respectfully.i think something is wrong here.What?
- anonimnystefy
- 2011-11-13 10:16:14
ok thanks for the help,and could sure use luck!I'm not sure about that brilliantly!
- bob bundy
- 2011-11-13 08:34:58
hi Stefy
Yes, that's what I think.
Good luck in the exams (not that you need it .. I'm sure you'll do brilliantly)
Bob
- anonimnystefy
- 2011-11-13 06:45:55
hi bob
yes,i have been occupied by school and my subjects.this was a crazy week.i'm glad it's over,but there is next week exams and i have physics, analysis and in the one after i have geometry and programming. very busy weeks! 
anyway,if i gave the restriction x<>0 then would my answers be correct?
- bob bundy
- 2011-11-12 19:43:09
hi Stefy,
Haven't 'spoken' to you in a while. Hope you are well.
Derivatives have to be 'well defined'. Specifically, this breaks down where the left limit isn't the same as the right limit.
So neither have a defined value at x = 0.
For |x| the deriv = 1 for x > 0 and -1 for x < 0.
How are you defining sgn(x) ?
If you mean 1 when x > 0 and -1 when X < 0, then zero is correct.
As this function is discontinuous at x = 0, I think you must exclude x = 0 from this derivative even though the value is the same either side of zero.
Bob
- anonimnystefy
- 2011-11-12 10:42:00
hi guys
i was wondering what derivatives of |x| and sgn(x) are.i thought of something but i got that they were sgn(x) and 0 respectfully.i think something is wrong here.What?