
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 four propositions, the correct proposition number is.  
① In $\triangle ABC$, $A > B$ is a necessary and sufficient condition for $\sin A > \sin B$;  
② The necessary and sufficient condition for the function $y=f(x)$ to have a zero point in the interval $(1,2)$ is $f(1) \cdot f(2) < 0$;  
③ In a geometric sequence $\{a_n\}$, if $a_1=1$ and $a_5=16$, then $a_3=\pm4$;  
④ After shifting the graph of the function $y=\sin(2-2x)$ to the right by 2 units, the corresponding equation of the graph is $y=\sin(4-2x)$.

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