
Normal at P $\begin{aligned}
& y+ t x=2 t+t^3 \
& \uparrow \
&(\mathrm{a}, 0) \
& \mathrm{at}= 2 \mathrm{t}+\mathrm{t}^3 \
& \mathrm{a}= 2+\mathrm{t}^2 \
& \mathbb{R}\left(2+\mathrm{t}^2, 0\right)
\end{aligned}\begin{aligned}
& \mathrm{PR}=4 \Rightarrow 4+4 \mathrm{t}^2=16 \
& 4 \mathrm{t}^2=12 \Rightarrow \mathrm{t}^2=3 \
& \mathrm{a}=5 \mathbb{R}(5,0)
\end{aligned}Focus(1,0)(1,0) &(5,0)willbethaendpts.ofdiameter\Rightarrow \mathrm{Eg}^{\mathrm{n}}ofcircleis\begin{aligned}
& (x-1)(x-5)+y^2=0 \
& x^2+y^2-6 x+5=0
\end{aligned}$