
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
Let the sides opposite to the angles $A$, $B$, $C$ in $\triangle ABC$ be $a$, $b$, $c$ respectively, with $b= \sqrt {3}$.  
$(1)$ If $C= \dfrac {5\pi}{6}$, and the area of $\triangle ABC$ is $\dfrac { \sqrt {3}}{2}$, find $c$;  
$(2)$ If $B= \dfrac {\pi}{3}$, find the range of values for $2c-a$.

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