MHT CET2017MathematicsThree Dimensional Geometry
The equation of the plane through ( − 1 , 1 , 2 ) , whose normal makes equal acute angle with co-ordinate axes is
Options
- Ar → ⋅ ( i ^ + j ^ + k ^ ) = 2
- Br → ⋅ ( i ^ + j ^ + k ^ ) = 6
- Cr → ⋅ ( 3 i ^ − 3 j ^ + 3 k ^ ) = 2
- Dr → . ( i ^ + j ^ + k ^ ) = 3
Correct answer
A. r → ⋅ ( i ^ + j ^ + k ^ ) = 2
Step-by-step solution
Equation plane passing through A ( a → ) and ⊥ to n → is r → . n → = a → . n → Here a → = - i ^ + j ^ + 2 k ^ , n → = i ^ + j ^ + k ^ ∴ r → ⋅ i ^ + j ^ + k ^ = - i ^ + j ^ + 2 k ^ . i ^ + j ^ + k ^ = 2