Given vectorsand
with
we can solve these equations by first taking the dot product of (1) wuthto give
The left hand side of this equation equals zero sinceis perpendicular to
so
Now use the identity
Substituteand
to give
Henceand
are multiples of each other or
Ifand
are multiples of each other, from (1)
and
are pendicular so both are 0 then from (2),
is arbitrary.
Ifthen from (1),
and
are parallel so