
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 $f(x)=-e^{x}-x$ and the function $g(x)=ax+2\cos x$, determine the range of values for $a$ such that there always exists a point on the graph of $g(x)$ where the tangent line $l_{2}$ is perpendicular to the tangent line $l_{1}$ at any point on the graph of $f(x)$.

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