How do you find the derivative of #f(x)=ln(root3(x-1)/(x+1))#?

Question

1300 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-03-08T00:42:56

#f'(x)=frac{-2(x-2)}{3(x-1)(x+1)}#

The derivative of #lnu = (u')/u#
Using this fact, we can derive #f(x)#

#f(x)=ln(frac{root3(x-1)}{x+1})#

#f'(x)=frac{(frac{(x+1)(1/3)(x-1)^(-2/3)-(x-1)^(1/3)}{(x+1)^2})}{(frac{(x-1)^(1/3)}{x+1})}#

#f'(x)=(frac{cancel((x-1)^(1/3))(frac{x+1}{3(x-1)}-1)}{(x+1)^2})(frac{x+1}{cancel((x-1)^(1/3))})#

#f'(x)=frac{(frac{x+1-3x+3}{3(x-1)})}{x+1}#

#f'(x)=frac{-2x+4}{3(x-1)(x+1)}#

#f'(x)=frac{-2(x-2)}{3(x-1)(x+1)}#