Let a, b, c be the sides of a triangle and let A, B, C be the respective angles. If `b+c=3a`, then find the value of the ratio `cos((B-C)/2)/cos((B+C)/2)`

Let a,b,c be the sides of a triangle ABC, a=2c,cos(A-C)+cos B=1. then the value of C is

Let A , B , C be the three angles such that A+B+C=pi . If T a nAtanB=2, then find the value of (cos(A-B))/(cosC)

Let A,B,C be the three angles such that A+B+C=pi , tan A.tan B=2 , then find the value of (cos A cos B)/(cos C)

If A,B,C are the angles of a triangle ABC that cos((3A+2B+C)/(2))+cos((A-C)/(2))=

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 Delta ABC, prove that :(b+c)cos((B+C)/(2))=a cos((B-C)/(2))])

In triangle ABC,a,b,c are the lengths of its sides and A,B,C are the angles of triangle ABC .The correct relation is given by (a) (b-c)sin((B-C)/(2))=a(cos A)/(2) (b) (b-c)cos((A)/(2))=as in(B-C)/(2)(c)(b+c)sin((B+C)/(2))=a(cos A)/(2)(d)(b-c)cos((A)/(2))=2a(sin(B+C))/(2)

If a, b, c are the sides of a triangle ABC and |(1,a,b),(1,c,a),(1,b,c)|=0, then the value of cos^2 A + cos^2 B +cos^2 C is equal to