Question 69
If the inequality
$$
sin^2 x + a \cos x + a^2 \ge 1 + \cos x
$$
holds for any $x \in \mathbb{R}$, the range of values for negative $a$ is
______.
$$
sin^2 x + a \cos x + a^2 \ge 1 + \cos x
$$
holds for any $x \in \mathbb{R}$, the range of values for negative $a$ is
______.