Mathematics · Straight lines

JEE Main 2025 — 28 January, Evening Shift — Question 2

Let A,B,C\mathrm{A}, \mathrm{B}, \mathrm{C} be three points in xy-plane, whose position vector are given by 3i^+j^,i^+3j^\sqrt{3} \hat{i}+\hat{j}, \hat{i}+\sqrt{3} \hat{j} and ai^+(1−a)j^a \hat{i}+(1-a) \hat{j} respectively with respect to the origin O. If the distance of the point C from the line bisecting the angle between the vectors OA→\overrightarrow{\mathrm{OA}} and OB→\overrightarrow{\mathrm{OB}} is 92\frac{9}{\sqrt{2}}, then the sum of all the possible values of a is :

  1. Option A:

    1

    Correct
  2. Option B:

    9/29 / 2

  3. Option C:

    0

  4. Option D:

    2

Answer: A

Step-by-step solution

Equation of angle bisector : x−y=0\mathrm{x}-\mathrm{y}=0

∣a−(1−a)2∣=92⇒a=5\left|\frac{\mathrm{a}-(1-\mathrm{a})}{\sqrt{2}}\right|=\frac{9}{\sqrt{2}} \Rightarrow a=5 or -4

Sum =5+(−4)=1=5+(-4)=1

Answer key and solution verified before publishing.

Practise Straight lines

Start with this question, then two more from the same chapter — with a tutor that explains every step. Free.

Exam
JEE Main 2025
Subject
Mathematics
Chapter
Straight lines
Topic
Angle between lines, perpendicular distance & distance between parallel lines, foot, image
Let A , B , C be three points in xy-plane, whose position vector are… | JEE Main 2025 PYQ with Solution · DhiX AI