$(16$ points$)$ A fluid with a dynamic viscosity of $=1\mathrm{.}8{10}^{-4}N*\frac{s}{m^2}$ flows past a flat surface. The fluid velocity $(u)$ is measured at several distances $(y)$ away from the surface and the results are tabulated below.

$\backslash$table$[[y(m),0,0\mathrm{.}006,0\mathrm{.}012,0\mathrm{.}018,0\mathrm{.}024],[u(\frac{m}{s}),0,0\mathrm{.}899,1\mathrm{.}915,3\mathrm{.}048,4\mathrm{.}299]]$

Use Newton's viscosity law, $=\frac{du}{dy},$ to estimate the shear stress $(\frac{N}{m^2}),$

$($a$)(8$ points$)$ at the surface $)=(0,$

$($b$)(8$ points$)$ at $y=0\mathrm{.}012.$

Use finite$-$difference formulas having best accuracy that is available to you below.