If log 4 = 1.3868 then log (4.01) =

$\begin{array}{rcl}\mathrm{x}& =& 4 \delta x=0.01 \mathrm{f}\left(\mathrm{x}\right)=\log \mathrm{x}\\ \mathrm{f}(\mathrm{x}+\delta x)& =& \frac{1}{\mathrm{x}}.\delta x+\mathrm{f}\left(\mathrm{x}\right)\\ & =& \frac{0.01}{4}+\log 4\\ & =& 1.368+0.0025\\ & =& 1.3893 \end{array}$