Show that the points whose position vectors are 
and 
are collinear.
let the given points are A, B, C with position vectors 
respectively so 
We know that equation of line passing through 
is
….(1)
If A, B, C are collinear then C must satisfy eq. (1)
On comparing the coefficient of 
on both sides of the equation 
for all 
Hence the points A, B, C are collinear.
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