20) Vector form If the equation of the line is
b
a
r
r
r
r
+λ
=
 and the equation of the plane is
r n
d
⋅
r r= Then the angle θ between the line and the
normal to the plane is
cos θ =
|
| |
|
bb n
n
⋅
⋅
rr r
r
and so the angle φ between the line and the plane is given by 90 – θ, i e