6. (i) (a) Express \(\frac { 7 x } { ( x + 3 ) ( 2 x - 1 ) }\) in partial fractions.
(b) Given that \(x > \frac { 1 } { 2 }\), find $$\int \frac { 7 x } { ( x + 3 ) ( 2 x - 1 ) } d x$$ (ii) Using the substitution \(u ^ { 3 } = x\), or otherwise, find $$\int \frac { 1 } { x + x ^ { \frac { 1 } { 3 } } } d x , \quad x > 0$$