
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
Let $A=\{x|2-a\leq x \leq 2+a\}$, and $B=\{x|(x-1)(x-4) \geq 0\}$.

(1) When $a=3$, find $A \cap B$;  
(2) If $a>0$, and $A \cap B = \emptyset$, find the range of the real number $a$.

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