
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 function $f(x)=x^{3}+ ax^{2}+a^{2}x -1$, where $a > 0$.

   (I) When $a=2$, find the intervals of monotonicity for the function $f(x)$;

   (II) If the inequality $f(x)\leqslant 0$ has solutions on the interval $[1,+\infty)$, find the range of values for $a$.

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