Most Important Selected Qs for JEE AdvancedMathematicsThree Dimensional Geometry
Paragraph: Let a₁ x+b₁ y+c₁ z+d₁=0 and a₂ x+b₂ y+c₂ z+d₂=0 be two planes, where d₁, d₂ 0 . Then origin lies in acute angle if a₁ a₂+b₁ b₂+c₁ c₂ 0 and origin lies in obtuse angle if a₁ a₂+b₁ b₂+c₁ c₂ 0 . Further point (x₁, y₁, z₁ ) and origin both lie either in acute angle or in obtuse angle, if (a₁ x₁+b₁ y₁+c₁ z₁+d₁ ) (a₂ x₁+b₂ y₁+c₂ z₁+d₂ ) 0 . One of (x₁, y₁, z₁ ) and origin lie in acute angle and the other in obtu
Options
- AO and P both lie in acute angle between the planes
- BO and P both lie in obtuse angle
- CO lies in acute angle, P lies in obtuse angle
- DO lies in obtuse angle, P lies an acute angle
Correct answer
B. O and P both lie in obtuse angle
Step-by-step solution
Equation of the second plane is -x+2 y-3 z+5=02(-1)+3,2+(-4)(-3) 0 origin lies in obtuse angle (2 1+3(-2)-4 3+7)(-1+2(-2)-3 3+5)=(2-6-12+7)(-1-4-9+5) 0 P lies in obtuse angle