
Calculus Calculus Math Forum 
 LinkBack  Thread Tools  Display Modes 
October 13th, 2013, 09:46 PM  #11 
Senior Member Joined: Oct 2013 From: Sydney Australia Posts: 126 Thanks: 0  Re: What does this mean: f' does not exist (1e derivative te
Ok thanks Greg, that's a weird function. 
October 14th, 2013, 02:32 AM  #12  
Senior Member Joined: Feb 2013 Posts: 281 Thanks: 0  Re: What does this mean: f' does not exist (1e derivative te
I didn't specify the domain of abs(x) because I supposed it is obvious what I mean, the whole R line. I apologize. Quote:
Undefined and nonexistence are synonymous in this context, at least the asker and me used it interchangeably. So I don't think it would be a grammar issue. Last edited by skipjack; January 19th, 2016 at 06:09 PM.  
October 14th, 2013, 05:02 AM  #13 
Senior Member Joined: Oct 2013 From: Sydney Australia Posts: 126 Thanks: 0  Re: What does this mean: f' does not exist (1e derivative te
ok, thanks for the education.

October 14th, 2013, 05:33 AM  #14  
Math Team Joined: Mar 2012 From: India, West Bengal Posts: 3,871 Thanks: 86 Math Focus: Number Theory  Re: What does this mean: f' does not exist (1e derivative te
A graphical explanation of differentiation might suffice to make OP understand : Differentiation of a function f at point x = x0 is the interior angle the tangent at x0 on the curve y = f(x) makes with xaxis  this is something basic I learned  by myself  before even looking at the formal definition of differentiation. Now, try to think about the point x = 0 of y = x and its neighborhoods. Plot the graph by yourself, to be sure. Now tell me this  do you see that there are infinitely many tangents drawable at x = 0? If you do, then do you realize that the derivative cannot be found there, since there are infinitely many angles formed by infinitely many tangents intersecting at xaxis? So, can you make a meaning of what "undefined" means? Quote:
Quote:
Last edited by skipjack; January 19th, 2016 at 06:13 PM.  

Tags 
derivative, exist, test 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
First Derivative Test  SamFe  Calculus  1  November 7th, 2013 01:04 PM 
Second Derivative Test  BrianMX34  Calculus  3  November 3rd, 2012 01:05 PM 
1st derivative test  mathkid  Calculus  5  October 6th, 2012 08:22 PM 
Second Derivative Test  SyNtHeSiS  Algebra  5  May 26th, 2010 05:28 AM 
Second derivative exist, but not continuos?  lime  Calculus  15  March 26th, 2009 02:12 AM 