Show that the line joining the origin to the point `(2, 1, 1)`is perpendicular to the line determined by the points`(3, 5, -1)`,`(4, 3, -1)`.

Explanation

Given,`l_1=2i+j​+k`

`l_2=(4−3)i+(3−5)j+(−1+1)k`

=`i−2j`

`l_1​​.l_2​`
​=`(2i+j​+k).(i−2j​)`

=`2−2`

=0

So, `l_1`​
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