
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 $f(x)=2\sqrt {3}\sin (ax- \dfrac {π}{4})\cos (ax- \dfrac {π}{4})+2\cos ^{2}(ax- \dfrac {π}{4})$ $(a > 0)$, and the function's smallest positive period is $\dfrac {π}{2}$.  
(I) Find the value of $a$;  
(II) Find the maximum and minimum values of $f(x)$ on the interval $\left[0, \dfrac {π}{4}\right]$.

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