
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 the function $f(x)=A\cos (ωx+φ)$, where $A$, $ω$, and $φ$ are constants, with $A > 0$ and $ω > 0$. If $f(x)$ is monotonic in the interval $[0, \frac {2π}{3}]$ and $f(- \frac {π}{3})=f(0)=-f( \frac {2π}{3})$, determine the value of $ω$.

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