
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
In $\triangle ABC$, $a$, $b$, $c$ are the sides opposite to angles $A$, $B$, $C$ respectively, and they satisfy $\frac{a+c}{a+b}=\frac{b-a}{c}$.

(1) Find the measure of angle $B$;

(2) If the longest side of $\triangle ABC$ has a length of $\sqrt{14}$, and $\sin A=2\sin C$, find the length of the shortest side.

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