
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 $ f_1(x) = (x^2 + 2x + 1)e^x $, $ f_2(x) = f'_1(x) $, $ f_3(x) = f'_2(x) $, ..., $ f_{n+1}(x) = f'_n(x) $, where $ n \in \mathbb{N^*} $. Let $ f_n(x) = (a_nx^2 + b_nx + c_n)e^x $, find the value of $ b_{2015} $.

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