Mathematics

Problem

Let

\vec{a}=(k,1,1)

\vec{b}=(1,k,1)

and

\vec{c}=(1,1,k)

. If

\vec{c}

is perpendicular to both

\vec{a}

and

\vec{b}

, find the value of

k

. a)

0

\dfrac{1}{2}

-\dfrac{1}{2}

-\dfrac{1}{3}