# How Good Are You In Vectors?

Geometry Level 3

If $$\vec { a } ,\vec { b } ,\vec { c }$$ are three vectors such that

$\large \begin{cases} \left| \vec { a } \right| =\left| \vec { c } \right| =1 \\ \left| \vec { b } \right| =4 \\ \left| \vec { b } \times \vec { c } \right| =2 \\ 2\vec { b } =\vec { c } +\lambda \vec { a } \end{cases}$

then $$\lambda$$, a scalar, can be:

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