
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 $α$ passes through the point $(a, 2a)$, where $a < 0$,

1. Find the values of $\cos α$ and $\tan α$.
2. Simplify and find the value of $\frac{\sin (π - α) \cos (2π - α) \sin (-α + \frac{3π}{2})}{\tan (-α - π) \sin (-π - α)}$.

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