11 Use the substitution \(2 x = \tan \theta\) to find the exact value of $$\int _ { 0 } ^ { \frac { 1 } { 2 } } \frac { 12 } { \left( 1 + 4 x ^ { 2 } \right) ^ { 2 } } d x$$ Give your answer in the form \(a + b \pi\), where \(a\) and \(b\) are rational numbers.
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