`a^2(cos^2B-cos^2C)+b^2(cos^2C-cos^2A)+c^2(cos^2A-cos^2B)=0` .

In any triangle A B C , prove that following: \ (cos^2B-cos^2C)/(b+c)+(cos^2C-cos^2A)/(c+a)+(cos^2A-cos^2B)/(a+b)=0

Prove: cot^2A cos e c^2B-cot^2B cos e c^2A=cot^2A-cot^2B .

If DeltaABC , prove that: a) sin^(2)A+sin^(2)B-sin^(2)C=2sinAsinBcosC b) cos^(2)A+cos^(2)B-cos^(2)C=1-2sinAcosBsinC c) cos^(2)A+cos^(2)B+cos^(2)C=1-2cosAcosBcosC

In any DeltaABC , prove that : (b^2 - c^2)/(cos B + cos C) + (c^2 - a^2)/(cos C + cos A) + (a^2 - b^2)/(cos A + cos B) = 0

In A B C Prove that cos^2A/2+cos^2B/2+cos^2C/2lt=9/4dot If cos^2A/2+cos^2B/2+cos^2C/2=y(x^2+1/(x^2)) then find the maximum value of ydot

If A+B=C, then cos^(2)A+cos^(2)B+cos^(2)C-2cosAcosBcosC=

In a triangle ABC, prove that: cos^4A+cos^4B+cos^4C= 3/2 + 2 cosA cosB cosC+ 1/2 cos 2A cos2B cos2C

If A+B+C=2S , prove that : cos^2 S + cos^2 (S-A) + cos^2 (S-B) + cos^2 (S-C) = 2+2cosA cosB cosC .

If A+B+C=180^0 , prove that : cos^2 (A/2) + cos^2 (B/2) - cos^2 (C/2) = 2cos (A/2) cos (B/2) sin (C/2)

In any DeltaABC , prove that : (b^2 - c^2) cos 2A + (c^2 - a^2) cos 2B + (a^2 - b^2) cos 2C =0