" 5) In "/_ABC" ,prove that: "(cos2A)/(a^(2))-(cos2B)/(b^(2))=(1)/(a^(2))-(1)/(b^(2))

In any DeltaABC , prove that (cos2A)/a^(2)-(cos2B)/b^(2)=(1/a^(2)-1/b^(2))

In any DeltaABC , prove that (cos2A)/a^(2)-(cos2B)/b^(2)=1/a^(2)-1/b^(2)

Prove that (cos^(2)A-sin^(2)B)+1-cos^(2)C

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

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

In any Delta ABC, prove that: (cos^(2)((A)/(2)))/(a)+(cos^(2)((B)/(2)))/(b)+(cos^(2)((c)/(2)))/(c)=(s^(3))/(abc)

In /_ABC, prove that cos ec(A)/(2)+cos ec(B)/(2)+cos ec(C)/(2)>=6

In Delta ABC prove that 2(b cos^(2)((C)/(2))-c cos^(2)((B)/(2)))=a+b+c

Prove that (1+cos(A-B)cosC)/(1+cos(A-C)cosB)=(a^(2)+b^(2))/(a^(2)+c^(2))

Prove that (1+cos(A-B)cosC)/(1+cos(A-C)cosB)=(a^(2)+b^(2))/(a^(2)+c^(2))