NDA 2016
- Exam
- NDA
- Year
- 2016
- Subject
- Mathematics
- Chapter
- Three Dimensional Geometry
NDA 2016 · Mathematics · Three Dimensional Geometry
Paragraph: Let Q be the image of the point P(-2,1,-5) in the plane...
Paragraph:
Let Q be the image of the point in the plane .
Question: Consider the following: 1. The coordinates of are . 2. PQ is of length more than 8 units. 3. The point is the mid-point of the line segment PQ and lies on the given plane. Which of the above statements are correct?
Question: Consider the following: 1. The coordinates of are . 2. PQ is of length more than 8 units. 3. The point is the mid-point of the line segment PQ and lies on the given plane. Which of the above statements are correct?
Options
- A1 and 2 only
- B2 and 3 only
- C1 and 3 only
- D1,2 and 3
Correct answer
D. 1,2 and 3
Step-by-step solution
Let be the image of the point .
The direction ratios of are ....(i)
The Equation of line is rP Q.
Let be such a point.
Let be the mid point of
Since lies on the plane
So, -2(1-r)+2(r-5)+1=0\Rightarrow r-17=0 \Rightarrow r=2Q(3 \times2-2,-2 \times2+1,2 \times2-5)=(4,-3,-1)P QL=\left(\frac{3 \times 2}{2}-2,1-2,2-5\right)=...(iii)
\therefore$ Option (4) is correct.