
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 vectors $\overrightarrow{a}=(2\sin x,\cos x)$ and $\overrightarrow{b}=( \sqrt {3}\cos x,2\cos x)$, define the function $f(x)= \overrightarrow{a} \cdot \overrightarrow{b}-1$. Find:
(I) The smallest positive period of the function $f(x)$;
(II) The interval(s) on which the function $f(x)$ is monotonically decreasing.

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