Explanation:
A The parametric equations of the parabola \(y^2=8 x\) are \(x=2 t^2\) and \(y=4 t\). and the given equation of circle is \(x^2+y^2-2 x-4 y=0\)
On putting \(x=2 t^2\) and \(y=4 t\) in circle, we get-
\(4 \mathrm{t}^4+16 \mathrm{t}^2-4 \mathrm{t}^2-16 \mathrm{t}=0\)
\(4 \mathrm{t}^4+12 \mathrm{t}^2-16 \mathrm{t}=0\)
\(4 \mathrm{t}\left(\mathrm{t}^3+3 \mathrm{t}-4\right)=0\)
\(\mathrm{t}(\mathrm{t}-1)\left(\mathrm{t}^2+\mathrm{t}+4\right)=0\)
\(\mathrm{t}=0, \mathrm{t}=1 \quad\left[\because \mathrm{t}^2+\mathrm{t}+4 \neq 0\right]\)
Thus the coordinates of points of intersection of the circle and the parabola are \(\mathrm{Q}(0,0)\) and \(\mathrm{P}(2,4)\). Clearly these are diametrically opposite points on the circle. The coordinates of the focus \(\mathrm{S}\) of the parabola are (2, 0 ) which lies on the circle.
\(\therefore\) Area of \(\triangle \mathrm{PQS}=\frac{1}{2} \times \mathrm{QS} \times \mathrm{SP}=\frac{1}{2} \times 2 \times 4\) \(=4\) sq. units.