Why is Anti Derivative of (1/x-3) Equal to -ln|x+3|?

  • Thread starter Thread starter elitespart
  • Start date Start date
  • Tags Tags
    Integral
elitespart
Messages
95
Reaction score
0
Why is the anti derivative of 1/(x-3) equal to -ln\left|x+3\right|. Why isn't it just ln\left|x-3\right|. Does it have something to do with the absolute value? Thanks.
 
Physics news on Phys.org
for negative x?

using just log |x-3| defines the differentiation function for pos x only
 
it's not -ln|x+3| and is in fact ln|x-3| . Take the derivative of your first answer and second and see which one works.
 
Alright so I'm guessing there was a typo. Thanks for your help.
 
d/dx (log |x-3|) != 1/(x-3)
for x element of (-inf, inf) for sure! edit: wrong

ooops.. my mistake. I was ignoring the absolute part
 
Last edited:
rootX said:
d/dx (log |x-3|) != 1/(x-3)
for x element of (-inf, inf) for sure!

For x \neq 3
 
the original function is undefined for x=3 also btw.
 
Back
Top