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 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]|

In triangle ABC , prove that (1) a=b cos C+c cos B (2) b=a cos C+c cos A .

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

cos2B + cos2A-cos2C = 1-4sin A sin B cos C

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

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 any triangle ABC, prove that following: a(cos B cos C+cos A)=b(cos C cos A+cos B)=c(cos A cos B+cos C)

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