1.Cosine of the angle between the vectors (a⃗+b⃗)(\vec{a} + \vec{b})(a+b) and (a⃗−b⃗)(\vec{a} - \vec{b})(a−b) if ∣a⃗∣=2|\vec{a}|=2∣a∣=2, ∣b⃗∣=1|\vec{b}|=1∣b∣=1 and the angle between a⃗\vec{a}a and b⃗\vec{b}b is 60∘60^\circ60∘, isa.37\frac{\sqrt{3}}{7}73b.921\frac{9}{\sqrt{21}}219c.37\frac{3}{\sqrt{7}}73d.noneLogin to continueOnly logged in users canattempt or see the solution.
