If y1(x) and y2(x) are two solutions of the differential equation
(cos x)y" + (sin x)y' - (1 + \(e^{-x^2}\))y = 0 \( \forall x \in\left(\frac{-\pi}{2}, \frac{\pi}{2}\right)\)
with y1(0) = \(\sqrt{2}, y_1^{\prime}(0)=1\), y2(0) = \(-\sqrt{2}, y_2^{\prime}(0)=2\),
then the Wronskian of y1(x) and y2(x) at \(x=\frac{\pi}{4}\) is
1
\(3 \sqrt{2}\)
2
6
3
3
4
\(-3 \sqrt{2}\)