
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 points A(2, 0), B(0, 2), C(cosα, sinα), and 0 < α < π  
(1) If $|\overrightarrow{OA} + \overrightarrow{OC}| = \sqrt{7}$, find the angle between $\overrightarrow{OB}$ and $\overrightarrow{OC}$;  
(2) If AC⊥BC, find the value of tanα.

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