29-6

$${B = \frac{\mu_0 i}{2 \pi} \int_0^{\infty} \frac{R}{\left( s^2 + R^2 \right)^{3/2}} \\ = \frac{\mu_0 i}{2 \pi R} \left[ \frac{s}{\left( s^2 + R^2 \right)^{1/2}} \right]_0^{\infty} = \frac{\mu_0 i}{2 \pi R}}$$