
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
The sum of the first $n$ terms of an arithmetic sequence ${a_n}$ is $S_n$. Given the function $f(x) = \frac{2^x - 1}{2^x + 1}$, with $f(a_2 - 2) = \sin\frac{2014π}{3}$ and $f(a_{2016} - 2) = \cos\frac{2015π}{6}$, find the value of ${S}_{2017}$.

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