If `A + B + C = pi` then prove that `cos A + cos B + cos C = 1 + 4 sin(A/2) .sin(B/2).sin(C/2)`

cos A + cos B + cos C = 1 + 4sin ((A) / (2)) sin ((B) / (2)) sin ((C) / (2))

a cos A + b cos B + c cos C = 2a sin B sin C

If A+B+C=pi then prove that cos A+cos B+cos C=1+4sin((A)/(2))*sin((B)/(2))*sin((C)/(2))

a.cos A + b.cos B + c.cos C = 2a sin B sin C

Prove that a cos A+b cos B+c cos C=4R sin A sin B sin C

If A+B+C=pi , prove that : cosA + cosB-cosC=4cos(A/2) cos(B/2) sin(C/2) -1

If A+B+C=180^0 , prove that : cos^2( A/2) + cos^2( B/2) + cos^2(C/2) = 2+2 sin(A/2) sin( B/2) sin( C/2)

If A+B+C=pi then prove that sin2A-sin2B+sin2C=4cos A sin B cos C

Theorem 3:cos A+cos B+cos C=1+4(sin A)/(2)(sin B)/(2)(sin 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))