`f(u) = u/{1 + lnu}`

`f'(u) = {(1+lnu)*((du)/(du)) - u*[d(1+lnu)/(du)]}/(1+lnu)^2`

`or, f'(u) = [(1+lnu) - (u/u)]/(1+lnu)^2`

`or, f'(u) = (1 + lnu - 1)/(1+lnu)^2`

`or, f'(u) = lnu/(1+lnu)^2`

``

` `

`f(u) = u/{1 + lnu}`

`f'(u) = {(1+lnu)*((du)/(du)) - u*[d(1+lnu)/(du)]}/(1+lnu)^2`

`or, f'(u) = [(1+lnu) - (u/u)]/(1+lnu)^2`

`or, f'(u) = (1 + lnu - 1)/(1+lnu)^2`

`or, f'(u) = lnu/(1+lnu)^2`

``

` `