
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
In triangle \(ABC\),

\[
\cos(2 \angle A - \angle B) + \sin(\angle A + \angle B) = 2.
\]

Find side \(BC\) if \(AB = 4\).

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