If Δ0 is the area of Δ formed by joining the points of contact of incircle with the sides of the given triangle whose area is Δ. Similarly Δ1,Δ2 and Δ3 are the corresponding area of the Δ formed by joining the points of contact of excircles with the sides. Prove that
ΔΔ1+ΔΔ2+ΔΔ3−ΔΔ0=2