
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 $\triangle ABC$ with the sides opposite to angles $A$, $B$, $C$ being $a$, $b$, $c$ respectively, and it satisfies $\frac {\sin (2A+B)}{\sin A}=2+2\cos (A+B)$.  
(I) Find the value of $\frac {b}{a}$;  
(II) If $a=1$ and $c= \sqrt {7}$, find the area of $\triangle ABC$.

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