
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 the terminal side of angle $\alpha$ passes through point P $\left(\frac{4}{5}, -\frac{3}{5}\right)$.

(1) Find the value of $\sin\alpha$.

(2) Calculate the value of $\frac{\sin\left(\frac{\pi}{2}-\alpha\right)}{\sin(\alpha +\pi)} \cdot \frac{\tan(\alpha-\pi)}{\cos(3\pi -\alpha)}$.

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