3.
$$\mathrm { f } ( x ) = \frac { 4 - 2 x } { ( 2 x + 1 ) ( x + 1 ) ( x + 3 ) } = \frac { A } { 2 x + 1 } + \frac { B } { x + 1 } + \frac { C } { x + 3 }$$
- Find the values of the constants \(A , B\) and \(C\).
- Hence find \(\int f ( x ) \mathrm { d } x\).
- Find \(\int _ { 0 } ^ { 2 } \mathrm { f } ( x ) \mathrm { d } x\) in the form \(\ln k\), where \(k\) is a constant.