/int_C (xdy-ydx) / (x^2 + y^2 + 1)

where C is the boundary of the minor segment of the circle x^2 + y^2 = 1 cut off by the chord x+y=1

I've sketched the graph and can see the segment needed but really don't know where to go with this one as i've not done one like this before.

Very fustrated!!!