1.If a⃗,b⃗,c⃗\vec{a}, \vec{b}, \vec{c}a,b,c and d⃗\vec{d}d are unit vectors such that (a⃗×b⃗)⋅(c⃗×d⃗)=1(\vec{a} \times \vec{b}) \cdot (\vec{c} \times \vec{d}) = 1(a×b)⋅(c×d)=1 and a⃗⋅c⃗=12\vec{a} \cdot \vec{c} = \frac{1}{2}a⋅c=21, thena.a⃗,b⃗,c⃗\vec{a}, \vec{b}, \vec{c}a,b,c are non-coplanarb.b⃗,d⃗\vec{b}, \vec{d}b,d are non-parallelc.a⃗,b⃗,d⃗\vec{a}, \vec{b}, \vec{d}a,b,d are non-coplanard.a⃗,d⃗\vec{a}, \vec{d}a,d are parallel and b⃗,c⃗\vec{b}, \vec{c}b,c are parallelLogin to continueOnly logged in users canattempt or see the solution.
