
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
A train departs from station A, accelerating at 0.5 km/min² for 2 minutes. It then travels at a constant speed for 7 minutes. After that, it decelerates at 0.5 km/min² and arrives at station B, where it stops for 2 minutes. Draw the speed-time graph for the train's journey from station A to station B. Also, find the distance-time relationship expression for the entire journey and determine the allowable range of time for this function.

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