
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 \( \triangle ABC \), the sides opposite to \(\angle A\), \(\angle B\), and \(\angle C\) are \(a\), \(b\), and \(c\) respectively. Given \(\frac{\cos B}{\cos C}=-\frac{b}{2a+c}\), find \(\angle B\).

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