
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
Let the universal set \\(U=\mathbb{R}\\), and the sets \\(A=\{x|1\leqslant x < 4\}\\), \\(B=\{x|2a\leqslant x < 3-a\}\\).

\\((1)\\) If \\(a=-2\\), find \\(B\cap A\\) and \\(B\cap \complement_U A\\).

\\((2)\\) If \\(A\cup B=A\\), find the range of the real number \\(a\\).

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