Explanation

(a)
Here, the focal chord to $y^{2} = 16x$ is tangent to circle $(x - 6)^{2} + y^{2} = 2\$
$\Rightarrow \$focus of parabola is (4, 0)
[image:11_image66.emf]
Now, tangent are drawn from $(4,\ 0)$ to$\ (x - 6)^{2} + y^{2} = 2$
Since, $PA$ is tangent to circle
$\tan{\theta = slope\ of\ tangent = \frac{AC}{AP} = \frac{\sqrt{2}}{\sqrt{2}}} = 1$
or $\tan{\theta = \frac{BC}{BP} = - 1\ }$
$\therefore$ Slope of focal chord as tangent to circle$= \pm 1$