
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 $f(x)= \sqrt {3}\sin x\cos x+\cos^{ 2 }x- \dfrac {1}{2}$, and in triangle $ABC$, the sides opposite to angles $A$, $B$, and $C$ are respectively $a$, $b$, and $c$, and $f(B)=1$.  
$(I)$ Find the magnitude of angle $B$;  
$(II)$ If $a= \sqrt {3},b=1$, find the value of $c$.

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