
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 $f(\alpha)= \frac {\sin( \frac {\pi}{2}+\alpha)+3\sin(-\pi-\alpha)}{2\cos( \frac {11\pi}{2}-\alpha)-\cos(5\pi-\alpha)}$.
(I) Simplify $f(\alpha)$;
(II) Given $\tan\alpha=3$, find the value of $f(\alpha)$.

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