Let P=(−1,0), Q=(0,0) and R=(3,33) be three points. The equation of the bisector of the angle PQR
(A)3x+y=0✓ Correct
(B)x+23y=0
(C)23x+y=0
(D)x+3y=0
Answer: (A)
Solution
Place the angle at Q=(0,0). The ray QP points toward (−1,0) along the negative x-axis at angle π, while QR toward (3,33) has slope 3 and makes angle 3π. The internal bisector lies at the mean direction 21(π+3π)=32π, whose slope is −3, giving the line 3x+y=0.
JEE Main · 2007 · 29 Apr 2007 · Offline · Single correct option