Limits Continuity And Differentiability

Let a, b \(\in\) R, b \(\in\) 0, Define a function

\(f(x) = \left\{ {\matrix{ {a\sin {\pi \over 2}(x - 1),} & {for\,x \le 0} \cr {{{\tan 2x - \sin 2x} \over {b{x^3}}},} & {for\,x > 0} \cr } } \right.\).

If f is continuous at x = 0, then 10 \(-\) ab is equal to ________________.