Question

In any triangle, show that alb cos C-C cos B] = 62-c?.​

Answer 1

Answer:

this is very dificult course

Step-by-step explanation:

only few people can do it

Answer 2

Solution :

We know, cosA=b2+c2−a22bc,cosB=c2+a2−b22ca,cosC=a2+b2−c22ab

∴L.H.S.=a(bcosC−ccosB)=a(b⋅a2+b2−c22ab−c⋅c2+a2−b22ca)

=12(a2+b2−c2−c2−a2+b2)=12(2b2−2c2)

=b2−c2=R.H.S.