
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
Determine the function(s) that are decreasing in the interval $(0, +\infty)$ among the following:
\[1] y = \tan x;\ [2] f(x) = x^2 - 3x;\ [3] f(x) = \frac{1}{x+1};\ [4] f(x) = -|x|. \]

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