
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Given that $\cos \alpha = -\frac{\sqrt{5}}{5}$, and $\alpha \in (\frac{\pi}{2}, \pi)$.
(I) Find the value of $\sin \alpha$;
(II) Find the value of $\frac{\sin(\frac{3\pi}{2} + \alpha) + 2\cos(\frac{\pi}{2} + \alpha)}{\cos(3\pi - \alpha)}$.

Present the answer in LaTex format: \boxed{Your answer}
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