Question

show that for vectors a and b
(a-b)*(a+b)=2(a*b)

Answer 1

a square - b square =2a×2b

Answer 2

Answer:

(a-b)*(a+b)=(a*a)+(a*b)-(b*a)-(b*b)

since a*a& b*b =0 and b*a = -(a*b)

⇒(a-b)*(a+b) =0+(a*b) +(a*b) -0

⇒(a-b)*(a+b) =2(a*b)

Step-by-step explanation: