Question

If a-b=3 and b-c =5 then find the value of a2+b2+c2-ab-bc-ca

Answer 1

We can write the expression as

(1/2)*[(a-b)^2 + (b-c)^2 +(c-a)^2]

Now put values

a-b = 3

b-c = 5

c-a = 1

Hwnce the rquired answer =

= (1/2)*[3^2 + 5^2+ 1^2]

1/2* 35

= 35/2