
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]


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Given $f(\alpha)= \frac{\sin (\alpha-3\pi)\cos (2\pi-\alpha)\cdot\sin (-\alpha+ \frac{3}{2}\pi)}{\cos (-\pi-\alpha)\sin (-\pi-\alpha)}$.  
$(1)$ Simplify $f(\alpha)$.  
$(2)$ If $\alpha$ is an angle in the third quadrant, and $\cos \left(\alpha- \frac{3}{2}\pi\right)= \frac{1}{5}$, find the value of $f(\alpha)$.

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