In a `/_\ABC , cosec A[sinB.cosC+cosB.sinC]=`
(A) `c/a`
(B) `a/c`
(C) 1
(D) none of these

If in a /_\ ABC, cosA.cosB+sinA.sinB.sinC =1,then (A) A=B (B) C=pi/2 (C) AC=BC (D) AB=sqrt(2) AC

In triangle ABC, if cosA+2cosB+cosC=2,t h e na ,b ,c are in (A) A.P. (B) G.P. (C) H.P. (D) none of these

If sinA+sinB+sinC=3 . Then: cosA+cosB+cosC= (a) 0 (b) 1 (c) 2 (d) 3

If A,B,C, are the angles of a triangle such that cot(A/2)=3tan(C/2), then sinA ,sinB ,sinC are in (a)AdotPdot (b) GdotPdot (c) HdotPdot (d) none of these

In triangle ABC , prove that a(cosC-cosB)=2(b-c)cos^2.(A)/(2) .

If A+C=2B, then (cosC-cosA)/(sinA-sinC)=

If in a DeltaABC , cos A + 2 cosB+cosC= 2 , then a,b, c are in

If sinA+sinB=C,&cosA+cosB=D , then sin(A+B)=?

In DeltaABC , prove that: a(cosC-cosB)=2(b-c)cos^(2)A/2