If \( y(\theta) = \frac{2 \cos \theta + \cos 2\theta}{\cos 3\theta + 4 \cos 2\theta + 5 \cos \theta + 2} \), then at \( \theta = \frac{\pi}{2} \), \( y'' + y' + y \) is equal to:
\( \frac{1}{2} \)
\( 1 \)
\( \frac{3}{2} \)
\( 2 \)