If →a,→b,→c are three vectors of magnitude √3,1,2 such that →a×(→a×→c)+3→b=→0 and θ is the angle between →a and →c, then cos2θ=

If →a,→b,→c are three vectors of magnitude √3,1,2 such that �

1.	If →a,→b,→c are three vectors of magnitude √3,1,2 such that →a×(→a×→c)+3→b=→0 and θ is the angle between →a and →c, then cos2θ=
Answer» If $\to a, \to b, \to c$ are three vectors of magnitude $\sqrt{3}, 1, 2$ such that $\to a \times (\to a \times \to c) + 3 \to b = \to 0$ and $θ$ is the angle between $\to a$ and $\to c$ , then ${cos}^{2} θ =$