(v)cos B-cos A=2((a-b)/(c))cos^(2)(C)/(2)

prove that: cos B-cos A=2((a-b)/(c))cos^(2)((C)/(2))

a(cos C-cos B)=2(b-c)cos^(2)(A)/(2)

In a triangle ABC if (sin2A+sin2B+sin2C)/(cos A+cos B+cos C-1)=((lambda)/(2))cos((A)/(2))cos((B)/(2))cos((C)/(2)) then lambda equals

In any Delta ABC, prove the following: (a+b+c)(cos A+cos B+cos C)=2((a cos^(2))(1)/(2)(A+b cos^(2))(1)/(2)(B+cos^(2))(1)/(2)C)

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))

(sin2A+sin2B+sin2C)/(cos A+cos B+cos C-1)=((lambda)/(2))(cos A)/(2)(cos B)/(2)(cos C)/(2) then lambda=

Show that a cos^(2)[(A)/(2)]+b cos^(2)[(B)/(2)]+c cos^(2)[(C)/(2)]=s+(D)/(R)

In any Delta ABC, prove that : (cos A)/(b cos C+c cos B)+(cos B)/(c cos A+a cos C)+(cos C)/(c cos B+b cos A)=(a^(2)+b^(2)+c^(2))/(2abc)

In any Delta ABC, prove that: (cos A)/(b cos C+c cos B)+(cos B)/(c cos A+a cos C)+(cos C)/(a cos B+b cos A)=(a^(2)+b^(2)+c^(2))/(2abc)

If A+B+C=180^(@) then cos2A+cos2B+cos2C=1-4cos A cos B cos C 2.If A+B+C=0 then cos A+cos B+cos C=-1+4(cos A)/(2)(cos B)/(2)(cos C)/(2)