Let P Q be a focal chord of the parabola $y^2=4 x$ such that it subtends an angle of $\frac{\pi}{2}$ at the point $(3,0)$. Let the line segment $P Q$ be also a focal chord of the ellipse $E \cdot \frac{x^2}{a^2}+\frac{y^2}{b^2}=1, a^2>b^2$. If $e$ is the eccentricity of the ellipse E , then the value of $\frac{1}{\mathrm{e}^2}$ is equal to :
