Is My Calculus Derivation Correct?

[Jason03]

My work is posted below...the problem seems pretty straight forward...but I am I don't think IM getting the correct answer...

any suggestions?

http://img221.imageshack.us/img221/742/calcek4.jpg

(finding first derivative)

 

[Hitman2-2]

My work is posted below...the problem seems pretty straight forward...but I am I don't think IM getting the correct answer...

any suggestions?

http://img221.imageshack.us/img221/742/calcek4.jpg

(finding first derivative)

I think everything looks fine up until the last equality:

<br /> \frac {dy} {dx} = \frac {1} {2} ( \frac {1} {x+1} - \frac {1} {x-1} )<br />

but

<br /> \frac {1} {2} ( \frac {1} {x+1} - \frac {1} {x-1} ) \neq \frac {1} {2x+1} - \frac {1} {2x-1}<br />

 

[physicsnoob93]

yeap hitman is right.

Careless error?

2(x+1) = 2x+2
and same goes for the next one.