If A,B and C are the angles of a triangle, then `|[-1+cos B, cos C+ cos B, cos B],[cos C+ cos A,-1+cos A, cos A],[-1+cos B,-1+cos A,-1]|`

If A , Ba n dC are the angels of a triangle, show that |-1+cos B cos C+cos B cos B cos C+cos A-1+cos A cos A-1+cos B-1+cos A-1|=0

If A,B,C are the angles of a triangal ,prove that : cos A +cos B + cos C = 1+r/R

If A, B and C denote the angles of a triangle, then Delta = |(-1,cos C,cos B),(cos C,-1,cos A),(cos B,cos A,-2)| is independent of

If A,B,C are the angles of triangle ABC, then the minimum value of |{:(-2,cos C , cos B),(cos C , -1, cos A ) , (cos B , cos A , -1):}| is equal to :

If A,B,C are the angles of triangle ABC, then the minimum value of |{:(-2,cos C , cos B),(cos C , -1, cos A ) , (cos B , cos A , -1):}| is equal to :

In a triangle ABC, a cos A+b cos B+ c cos C=

In a triangle ABC, cos A+cos B+cos C=

If A,B,C are the angles of a triangle then prove that cos A+cos B-cos C=-1+4cos((A)/(2))cos((B)/(2))sin((C)/(2))

In any triangle, (1+ cos (A-B)cos C)/(1+cos (A-C)cos B)=