
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
(1) Given an angle $α$ with a point $P(-4,3)$ on its terminal side, find the value of $\dfrac {\cos ( \dfrac {π}{2}+α)\sin (-π-α)}{\cos ( \dfrac {11π}{2}-α)\sin ( \dfrac {9π}{2}+α)}$.  
(2) Let $k$ be an integer, simplify $\dfrac {\sin (kπ-α)\cos [(k+1)π-α]}{\sin [(k-1)π +α ]\cos (kπ +α )}$.

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