cos^(2)-b^(2)-a-b

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

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

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

If tan A tan B=sqrt((a-b)/(a+b)), prove that (a-b cos2A)(a-b cos2B)=a^(2)-b^(2)

If tan A tan B=sqrt((a-b)/(a+b)) show that (a-b cos2A)(a-b cos2B)=a^(2)-b^(2)

Prove that cos(A+B)cos(A-B)=cos^(2)A-sin^(2)B=cos^(2)B-sin^(2)A

If cos^(2)A-sin^(2)A=tan^(2)B, prove that 2cos^(2)B-1=cos^(2)B-sin^(2)B=tan^(2)A

sin^(2)A cos^(2)B-cos^(2)A sin^(2)B=sin^(2)A-sin^(2)B

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

In a triangle ABC the maximum value of (a cos^(2)A//2 +b cos^(2)B//2+cos^(2)C//2)/(a+b+c) is