
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
Among the following propositions, "p is a sufficient but not necessary condition for q" is (fill in the serial number):

(1) p: $a=0$, q: $f(x)=x^2+ax$, ($x\in\mathbb{R}$) is an even function;  
(2) p: $\sin\alpha>\sin\beta$, q: $\alpha>\beta$;  
(3) p: $\log_a=\log_b$, q: $a=b$;  
(4) p: $x\in M\cap N$, q: $x\in M\cup N$.

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