Tính: a) \(\int\limits_0^{\frac{\pi }{4}} {{{\sin }^2}\frac{x}{2}dx} \); b) \(\int\limits_0^1 {\left( {3x - 4{x^3}} \right)dx - \int\limits_1^2 {\left( {4{x^3} - 3x} \right)dx} } \); c) \(\int\limits_0^6 {\left( {\left| {2x - 2} \right| + 4{x^2}} \right)dx} \).

Tính:

a) \(\int\limits_0^{\frac{\pi }{4}} {{{\sin }^2}\frac{x}{2}dx} \);

b) \(\int\limits_0^1 {\left( {3x - 4{x^3}} \right)dx - \int\limits_1^2 {\left( {4{x^3} - 3x} \right)dx} } \);

c) \(\int\limits_0^6 {\left( {\left| {2x - 2} \right| + 4{x^2}} \right)dx} \).