Let a and b be two unit vectors such that the angle is π/4.

Question

Let \(\hat{a}\) and \(\hat {b}\) be two unit vectors such that the angle between them is π/4 . If θ is the angel between the vectors \((\hat{a}+\hat{b})\) and \((\hat{a}+2\hat{b}+ 2(\hat{a}\times\hat{b}))\) , then the value of 164 cos2 q is equal to : 

(A) 90 + 27√2

(B) 45 + 18√2

(C) 90 + 3√2

(D) 54 + 90√2

Answer 1

Correct option is (A) 90 + 27√2