(1-cos A+cos B-cos(A+B))/(1+cos A-cos B-cos(A+B))

If A+ B + C = pi, then cos^(2) A + cos ^(2) B + cos ^(2) C is equal to : A) 1 - cos A cos B cos C B) 1 - 2 cos A cos B cos C C) 2 cos A cos B cos C D) 1 + cos A cos B cos C

If A+B+C=0, then the value of sin^(2)A+cos C(cos A cos B-cos C)+cos B(cos A cos C-cos B) is equal to: -1 (b) 0(c)1 (d) none of these

(cos A-cos B+cos C+1)/(cos A+cos B+cos C-1) =

In Delta ABC, show that (1-cos A+cos B+cos C)/(1-cos C+cos A+cos B)=tan((A)/(2))cot((C)/(2))

cos(A + B) cos (A-B) =

1-cos A + cos B-cos (A + B) * AB tan-cot-1 + cos A-cos B-cos (A + B) cod-cod CO-coc0-ces-A cos

Prove the following : cos2A+cos2B+cos2(A-B)+1 = 4cosA.cosB.cos(A-B)

If A+B+C=180^(@) , then (cos2A+cos2B+cos2C+1)/(cos A cos B cos C)

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

If A + B + C =180^@ , prove that : cos^2 A+ cos^2 B+cos^2 C=1-2 cos A cos B cosC .