Skip to content
dronacharya.ai
← JEE Main 2015 · 4 Apr · Shift 1
MathematicsSingle correct+4 / -1Question 79 of 90

JEE Main 2015 · 4 Apr · Shift 1, Mathematics question 79

Locus of the image of the point (2, 3) in the line (2x−3y+4)+k(x−2y+3)=0(2x-3y+4)+k(x-2y+3)=0, k∈Rk\in\mathbb R, is a :

Choose one option
Answer and worked solution

Official answer: C

Every line of the family passes through the intersection of 2x−3y+4=02x-3y+4=0 and x−2y+3=0x-2y+3=0, which is (1, 2). Reflection keeps the distance from (1, 2): 1+1=2\sqrt{1+1}=\sqrt2.

So the image lies on a circle of radius 2\sqrt2 about (1, 2).