Question
Find the angle between the two planes
2 x + y – 2 z = 5 and 3x – 6 y – 2 z = 7 using vector method.
Solution
The equations of two planes are
2x + y – 2 z = 5 and 3x – 6y –2 z = 7
These equations can be written as
and 
or 
Also, 
Let θ be the angle between the planes
