
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 $α$ is an angle in the third quadrant, $f(α)= \dfrac {\\sin (α- \dfrac {π}{2})\\cdot \\cos ( \dfrac {3π}{2}+α)\\cdot \\tan (π-α)}{\\tan (-α -π )\\cdot \\sin (-α -π )}$.

1. Simplify $f(α)$;
2. If $\cos (α- \dfrac {3π}{2})= \dfrac {1}{5}$, find $f(α+ \dfrac {π}{6})$.

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