Q. The equation of line through the point (1, 1) and making angles of $45{^\circ}$ with the line $x + y = 0$ are
A) $x - 1 = 0,\ x - y = 0$
B) $x - 1 = 0,\ y - 1 = 0$
C) $x - y = 0,\ y - 1 = 0$
D) $x + y - 2 = 0,\ y - 1 = 0$
Explanation
(b)
Since, the required lines make an angle $45{^\circ}$ either above the line or below the line
$\therefore\$Required slopes are
$m = 90{^\circ},\ 180{^\circ}$
$\therefore y - 1 = \tan{90{^\circ}}(x - 1)$
$\Rightarrow x = 1$
and $y - 1 = \tan{180{^\circ}}(x - 1)$
$\Rightarrow y = 1$
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Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.