In triangle ABC, prove that `cos(A/2)+cos(B/2)+cos(C/2)=4cos(pi-A)/4cos(pi-B)/4cos(pi-C)/4`

In triangle ABC,prove that cos((A)/(2))+cos((B)/(2))+cos((C)/(2))=4(cos(pi-A))/(4)(cos(pi-B))/(4)(cos(pi-C))/(4)

If A +B+C = 180^circ , prove that cos A/2+ cos B/2 +cos C/2 = 4cos (pi-A)/4 * cos(pi-B)/4 cos(pi-C)/4

If A+B+C=pi then prove that cos((A)/(2))+cos((B)/(2))+cos((C)/(2))=4cos((pi-A)/(4))cos((pi-B)/(4))cos((pi-C)/(4))

If in a triangle ABC, if 4Rr cos((A)/(2))cos((B)/(2))cos((C)/(2))=

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

Prove that 4cos((2pi)/7).cos(pi/7)-1=2cos((2pi)/7) .

If A+B+C=2S, then prove that cos(S-A)+cos(S-B)+cos C=-1+4cos((S-A)/(2))cos((S-B)/(2))cos((C)/(2))

Prove that cos((2pi)/7)cos((4pi)/7)cos((8pi)/7)=1/8

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))

Prove that: cos(pi/4+A)+cos(pi/4-A)=sqrt(2)cosA