
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 the function $f(x)=\sin x-a\cos x$, one of the symmetry axes of its graph is $x= \frac {3}{4}π$. Let the two extreme points of the function $f(x)$ be $x_{1}$ and $x_{2}$. Find the minimum value of $|x_{1}+x_{2}|$.

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