
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 plane, there is point A(2,0), point C(cosα, sinα), where α ∈ (0, π), and point O is the origin. The magnitude of vector $\overrightarrow{OA} + \overrightarrow{OC}$ is $\sqrt{7}$.
(1) Find the value of α.
(2) Find the angle between vector $\overrightarrow{OA}$ and vector $\overrightarrow{AC}$.

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