The line xcos alpha + ysin alpha = pwill be a | vedclass

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(d) $x\cos \alpha + y\sin \alpha - p = 0$ is a tangent, if perpendicular from centre on it is equal to radius of the circle.

Here centre is $(a\cos

Vedclass · Accepted Answer

$0$ or $2a$

Vedclass · Answer

(d) $x\cos \alpha + y\sin \alpha - p = 0$ is a tangent, if perpendicular from centre on it is equal to radius of the circle.

Here centre is $(a\cos \alpha ,\;a\sin \alpha )$ and radius is $a$.

$\left| {\frac{{a{{\cos }^2}\alpha + a{{\sin }^2}\alpha - p}}{{\sqrt 1 }}} \right| = a$

$i.e.$ $|a - p|\; = a \Rightarrow p = 0$ or $p = 2a$.

The line $x\cos \alpha + y\sin \alpha = p$will be a tangent to the circle ${x^2} + {y^2} - 2ax\cos \alpha - 2ay\sin \alpha = 0$, if $p = $

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