
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 $f(x)= \overrightarrow{a} \cdot \overrightarrow{b}$, where vectors $\overrightarrow{a}=(2\cos x,1)$ and $\overrightarrow{b}=(\cos x, \sqrt {3}\sin 2x), x\in R$.
(1) Find the interval(s) where the function $f(x)$ is monotonically decreasing;
(2) If $x\in\left[- \frac {\pi}{4},0\right]$, find the range of the function $f(x)$.

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