english: The area of the large square is therefore ( b − a ) 2 + 4 a b 2 = ( b − a ) 2 + 2 a b = b 2 − 2 a b + a 2 + 2 a b = a 2 + b 2
non_english: в€’ 2 a a' в€’ 2 b b' + 2 a a' b b' < в€’a 2 в€’ b 2 в€’ a' 2 в€’ b' 2 + a 2 b' 2 + a' 2 b 2