
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 that O is the origin of coordinates, vector $\overrightarrow {OA} = (\sin\alpha, 1)$, $\overrightarrow {OB} = (\cos\alpha, 0)$, $\overrightarrow {OC} = (-\sin\alpha, 2)$. Point P is a point on line AB, and $\overrightarrow {AB} = \overrightarrow {BP}$.  
(Ⅰ) If points O, P, and C are collinear, find the value of $\tan\alpha$;  
(Ⅱ) Under the condition of (Ⅰ), find the value of $\frac {\sin2\alpha+\sin\alpha}{2\cos2\alpha+2\sin^{2}\alpha+\cos\alpha}+\sin2\alpha$.

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