Question

The equations of the tangents at the ends of latusrectum of $y^2=4ax$ are

• A. $x\pm y-a=0$
• B. $x\pm y+a=0$
• C. $x\pm y-3a=0$
• D. $x\pm y+2a=0$

Answer 1

Answer: (B)

$x\pm y+a=0$

Coordinates of end point of latus rectum of parabola $y^2=4ax$ are, $(a,2a)$ and $(a,-2a)$
Hence equation of tangents at these points are given by,
$y\pm 2a=\pm (x-a)\Rightarrow x\pm y+a=0$