计算下列定积分:-|||-(1) (int )_(-dfrac {pi )(2)}^dfrac (pi {2)}(dfrac (cos x)(2+sin x)+(x)^2sin x)dx .-|||-(2) (int )_(0)^dfrac (pi {2)}dfrac (x)(1+cos x)dx .-|||-(3) (int )_(0)^dfrac (pi {2)}dfrac (sin x-cos x)(1+sin 2x)dx :-|||-(4) (int )_(-2)^2((x)^3cos dfrac (x)(2)+dfrac (1)(2))sqrt (4-{x)^2}dx =-|||-(5) (int )_(-dfrac {pi )(2)}^dfrac (pi {2)}dfrac (x+{sin )^2x}({(1+cos x))^2}dx =-|||-(6) (int )_(0)^dfrac (x{2)}dfrac (dx)({(cos x+2sin x))^2}-|||-(7) (int )_(-1)^1dfrac ({x)^2}(1+sqrt {1-{x)^2}}dx .-|||-(8) (int )_(0)^pi dfrac (x|sin xcos x|)(1+{sin )^4x}dx,