Incentre \[I(z)\] of the triangle ABC is the point of concurrence of internal bisectors of angle of triangle ABC and is given by \[\frac{az_1+bz_2+cz_3}{a+b+c}\]
where \[ A(z_1)\] ,\[ B(z_2)\] ,\[ C(z_3)\] are the coordinates of the vertex A,B,C respectively.
a,b,c are the lengths of the sides opposite to vertex A,B,C respectively.
Let \[ z_1=1+i\] \[ z_2=2+3i\] and \[ z_3=5-4i\] and a=3 b=5 and c=6
we get \[I(z)=\frac{3(1+i)+5(2+3i)+6(5-4i)}{3+5+6}\]
