
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 the quadrilateral \(ABCD\), it is given that \(\cos \angle BAD = \frac{3}{4}\), \(\angle BAC = \angle DAC\), \(AD < AB\), and \(AB = 5\), \(AC = BD = \sqrt{14}\). If \(\overrightarrow{AC} = \lambda \overrightarrow{AB} + \mu \overrightarrow{AD}\) (\(\lambda, \mu \in \mathbf{R}\)), find \(\lambda + \mu\).

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