If
\[
y = (\sin^{-1} x)^2 + (\cos^{-1} x)^2,
\]
then
\[
(1 - x^2) \frac{d^2y}{dx^2} - x \frac{dy}{dx} =
\]
Show Hint
When differentiating inverse trigonometric functions, remember the key identities such as \( \sin^{-1} x + \cos^{-1} x = \frac{\pi}{2} \). This helps in simplifying the given expressions.