
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 statements, the correct ones are \_\_\_\_\_\_.
① The set of angles whose terminal sides fall on the y-axis is $$\{α|α= \frac {kπ}{2}, k∈Z\}$$;  
② A center of symmetry for the graph of the function $$y=2\cos(x- \frac {π}{4})$$ is $$( \frac {3π}{4}, 0)$$;  
③ The function y=tanx is increasing in the first quadrant;  
④ To obtain the graph of the function y=sin(2x- $$\frac {π}{3}$$), it is only necessary to shift the graph of the function y=sin2x to the right by $$\frac {π}{6}$$ units.

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