Here, we have the three trigonometric functions as cosA,cosB and cosC. ∴ let f(x)=cosx; which can be plotted as;Now, let us suppose any three points x=A,x=B,x=C on f(x)=cosx. So that A+B+C=π or on the interval of length π.where G, be centroid of Δ given by(3A+B+C​,3cosA+cosB+cosC​)Thus, from figure points Q, G, P arecollinear,where; ordinate of GQ< ordinate of PQ.3cosA+cosB+cosC​