
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 a function $f(x)=ax^{2}+bx+k$ ($k > 0$), which attains an extremum at $x=0$, and the tangent line at the point $(1,f(1))$ is perpendicular to the line $x+2y+1=0$.

(I) Find the values of $a$ and $b$;

(II) Discuss the monotonicity of the function $g(x)= \dfrac {e^{x}}{f(x)}$.

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