
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 the universal set $U=\mathbb{R}$, the domain of the function $y= \sqrt{x} + \sqrt{3-x}$ is denoted as $A$, and $B=\{y|y=2^x, 1\leq x\leq 2\}$, find:  
(1) The sets $A$ and $B$;  
(2) $(\complement_U A) \cap B$.

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