Limits Continuity And Differentiability

If the function

$$f(x)= \begin{cases}\frac{1}{|x|}, & |x| \geqslant 2 \\ \mathrm{a} x^2+2 \mathrm{~b}, & |x|<2\end{cases}$$

is differentiable on \(\mathbf{R}\), then \(48(a+b)\) is equal to __________.