
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
(This question is worth a total of 14 points)  
Through observation, it has been found that the energy consumed by salmon swimming upstream at a constant speed in a river is $E = kv^3t$, where $v$ is the speed of the salmon in still water, $t$ is the time of travel (in hours), and $k$ is a positive constant. If the speed of the water flow is 3 km/h, and the salmon swims upstream for 100 km.  
(1) Express the energy $E$ consumed by the salmon as a function of $v$;  
(2) At what value of $v$ is the energy consumed by the salmon minimized?

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