∫(0→2π)f(x-π)dx=∫(0→π)f(x-π)dx+∫(π→2π)f(x-π)dx=-x| 0→π +∫(π→2π)xsinxdx =-π-∫(π→2π)xdcosx=-π-[(xcosx)--∫(π→2π)cosxdx =-π-[(xcosx)|π→2π -∫(π→2π)cosxdx] =-π-(2π+π-0)=-4π
