
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 certain company's new product must rely on advertising to open up the market. The advertising effectiveness $y$ (in yuan) is the difference between the sales amount and the advertising cost $x$ (in yuan). If the sales amount is proportional to the square root of the advertising cost, and based on market sampling surveys, every 100 yuan spent on advertising yields a sales amount of 1000 yuan.
(Ⅰ) Determine the functional relationship between the advertising effectiveness $y$ and the advertising expense $x$;
(Ⅱ) How much should the company invest in advertising to get the maximum advertising effectiveness? Is it true that the more they invest in advertising, the better?

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