
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 $\triangle ABC$, it is known that $AC=3$, and the three interior angles $A$, $B$, $C$ form an arithmetic sequence.  
(1) If $\cos C= \frac{\sqrt{6}}{3}$, find $AB$;  
(2) Find the maximum area of $\triangle ABC$.

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