# Mad with triangle (Part 1)

Geometry Level pending

Let $$a,b,c$$ denote the sides of a triangle, with opposite angles $$A,B,C$$ respectively, and let $$\Delta$$ denote the area of the triangle.

The value of $$\dfrac{\tan(A/2)}{(a-b)(a-c)} + \dfrac{\tan(B/2)}{(b-a)(b-c)} + \dfrac{\tan(C/2)}{(c-a)(c-b)}$$ is equal to:

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