Question

if a^2+b^2+c^2-ab-bc-ac=0,prove a=b=c

Answer 1

a^2+b^2+c^2-ab-bc-vs=0
or 1/2 (2a^2+2b^2+2c^2-2ab-2bc-2ca)=0
the proof is shown in the above pic

@sumo