
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 $\triangle ABC$, the sides opposite to angles $A$, $B$, $C$ are $a$, $b$, $c$ respectively. Given that the area of $\triangle ABC$ is $3\sin A$, the perimeter is $4(\sqrt{2}+1)$, and $\sin B + \sin C = \sqrt{2}\sin A$.

(1) Find the values of $a$ and $\cos A$.
(2) Find the value of $\cos (2A-\frac{\pi }{3})$.

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