Past exam of the mathematics course of the year 1 of the natural sciences course of the University of Cambridge / 2014 / Paper 2 / 18 / c / Solution

For the composite square root, $y>1$ throughout the restricted $x$ interval. Differentiate with respect to $y$:The second expression comes from differentiating both $y^{-1}$ and $(\log y{)}^{-1/2}$. The endpoints where $y=1$ are excluded here.