A(-1,0) B(1,0)
∫L (x+y)dx+(y-x)dy
=∫(L+AB) (x+y)dx+(y-x)dy -∫(AB) (x+y)dx+(y-x)dy 运用格林公式
=-2∫∫Q dxdy -∫(-1,1) xdx
=-π/2 -x^2/2|(-1,1)
=-π/2-1/2+1/2
=-π/2
A(-1,0) B(1,0)
∫L (x+y)dx+(y-x)dy
=∫(L+AB) (x+y)dx+(y-x)dy -∫(AB) (x+y)dx+(y-x)dy 运用格林公式
=-2∫∫Q dxdy -∫(-1,1) xdx
=-π/2 -x^2/2|(-1,1)
=-π/2-1/2+1/2
=-π/2