
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
The sequence number of the true proposition is $\boxed{\text{answer}}$.

$①y=\\sin |x|$ and $y=\\sin x$ are symmetric about the $y$-axis.

$②y=\\cos (-x)$ and $y=\\cos |x|$ have the same graph.

$③y=|\\sin x|$ and $y=\\sin (-x)$ are symmetric about the $x$-axis.

$④y=\\cos x$ and $y=\\cos (-x)$ are symmetric about the $y$-axis.

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