Let 
and 
Then,
If 
and 
show that no value of 
can make 
and 
coplanar.
Formula: -
and
then,
(iii)Three vectors 
are coplanar if and only if
we know that 
are coplanar if
now, using
⇒ 0 – 1(c3) + 1(2) = 0
⇒ c3 = 2
12
Let and Then,
If and show that no value of can make and coplanar.
Formula: -
andthen,
(iii)Three vectors are coplanar if and only if
we know that are coplanar if
now, using
⇒ 0 – 1(c3) + 1(2) = 0
⇒ c3 = 2