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

?

]]>i guess sgn(x) can be done similairly.

]]>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?

]]>

Yes, that's what I think.

Good luck in the exams (not that you need it .. I'm sure you'll do brilliantly)

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?

]]>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

]]>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?

]]>