JEE MainMathematicsStraight Lines and Pair of Straight LinesMCQ+4 / −1
The distance between the two points A and A' which lie on y = 2 such that both the line segments AB and A' B (where B is the point (2, 3)) subtend angle at the origin, is equal to :
- A10
- B
- C
- D3
View written solutionFree
Correct answer: C
- Set up the geometry
Let the required points on the line be Given point:
We are told that the line segments and each subtend an angle at the origin.
That means the angle between the lines and is , and similarly for and .
So we need all points such that
- Use slope formula for angle between two lines
Slope of :
Slope of :
Angle between two lines with slopes is given by
Here , so . Therefore,
Simplify:
Multiply numerator and denominator by :
So,
- Solve the equation
This gives two cases:
Case 1
Case 2
Thus the two points are
- Find the distance between and
Since both points lie on the horizontal line , their distance is just the difference of their -coordinates:
- Compare with options
corresponds to Option C.
- Verification with stored answer
Stored correct answer: C
Derived answer: C
They agree.
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