
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
Given that the function $f(x)$ is an even function defined on $\mathbb{R}$, and for any $x \geqslant 0$, it holds that $f(x+2)=-f(x)$. When $x \in [0,1]$, $f(x)=2^{x}-1$. Evaluate $f(-2017)+f(2018)$.

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