MCQ
Volume of purullclopipcd determined by vectors $\vec a + \vec b,\vec b + \vec c$ and $\vec c + \vec a$ is $4$. Then the volume of the parallelopiped determined by vectors $\vec a \times \vec b,\vec b \times \vec c$ and $\vec c \times \vec a$ is
  • A
    $24$
  • B
    $16$
  • C
    $8$
  • $4$

Answer

Correct option: D.
$4$
d
$[\vec{a}+\vec{b} \quad \vec{b}+\vec{c} \quad \vec{c}+\vec{a}]=4 \Rightarrow[\vec{a} \vec{\,b} \vec{\,c}]=2$

New volume $=[\vec{a} \times \vec{b} \quad \vec{b} \times \vec{c} \quad \vec{c} \times \vec{a}]$

$=\left[\begin{array}{lll}{\vec{a}} & {\vec{b}} & {\vec{c}}\end{array}\right]^{2}=4$

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