
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 an angle $\alpha$ and a point P(-3, 4) on the terminal side of $\alpha$, find:  
(1) The values of $\sin\alpha$ and $\cos\alpha$  
(2) The value of $$\frac {\cos( \frac {\pi}{2}+\alpha)-\sin(-\pi-\alpha)}{\cos( \frac {11\pi}{2}-\alpha)+\sin( \frac {9\pi}{2}+\alpha)}$$.

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