
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 $f(x)=\cos x\cos (x+ \frac {π}{3}).$
(1) Find the range of $f(x)$ in the interval $[0, \frac {π}{2}];$
(2) If $f(θ)= \frac {13}{20}$, where $- \frac {π}{6} < θ < \frac {π}{6}$, find the value of $\cos 2θ$.

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