Step-by-step explanation: Correct option is C 3 π Normal vector of plane x+y+2z=6 is a = i ^ + j ^ +2 k ^ and normal vector to the plane 2x−y+z=9 is b =2 i ^ − j ^ + k ^ Note: Angle between the plane is same as angle between their normals Thus angle between above planes is =cos −1 ∣ a ∣∣ b ∣ a ⋅ b =cos −1 6 6 2−1+2 =cos −1 2 1 = 3 π Reply
Step-by-step explanation:
Correct option is
C
3
π
Normal vector of plane x+y+2z=6 is
a
=
i
^
+
j
^
+2
k
^
and normal vector to the plane 2x−y+z=9 is
b
=2
i
^
−
j
^
+
k
^
Note: Angle between the plane is same as angle between their normals
Thus angle between above planes is =cos
−1
∣
a
∣∣
b
∣
a
⋅
b
=cos
−1
6
6
2−1+2
=cos
−1
2
1
=
3
π