
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 function $f(x)$ defined on $\mathbb{R}$ satisfies $f(x+2)=-f(x)$, and when $x\in[-1,1]$, $f(x)=x^{3}$.
(1) Find the expression of $f(x)$ on $[1,5]$;
(2) If $A=\{x|f(x) > a,x\in\mathbb{R}\}$, and $A\neq \varnothing$, find the range of the real number $a$.

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