Step 1: Construct the equilateral triangle. Let the two parallel lines be \( y = 0 \) and \( y = 5 \), with \( P(0,1) \) lying between them. Since \( POR \) is an equilateral triangle, we use rotational symmetry to compute the coordinates of \( Q \) and \( R \).
Step 2: Compute the side length. Using coordinate transformations, we find the side length of \( \triangle POR \) is \( 4\sqrt{3} \).
Step 3: Compute \( QR^2 \). Since \( QR = 4\sqrt{3} \), squaring it gives: \[ (QR)^2 = 48. \]
Thus, the answer is \( \boxed{48} \).
Let \( y = y(x) \) be the solution of the differential equation \[ 2\cos x \frac{dy}{dx} = \sin 2x - 4y \sin x, \quad x \in \left( 0, \frac{\pi}{2} \right). \] \( y\left( \frac{\pi}{3} \right) = 0 \), then \( y\left( \frac{\pi}{4} \right) + y\left( \frac{\pi}{4} \right) \) is equal to ________.
For some \( a, b \), let \( f(x) = \left| \begin{matrix} a + \frac{\sin x}{x} & 1 & b \\ a & 1 + \frac{\sin x}{x} & b \\ a & 1 & b + \frac{\sin x}{x} \end{matrix} \right| \), where \( x \neq 0 \), \( \lim_{x \to 0} f(x) = \lambda + \mu a + \nu b \).
Then \( (\lambda + \mu + \nu)^2 \) is equal to: