
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
Let $\{a\_n\}$ be an arithmetic sequence with $S\_n$ denoting the sum of its first $n$ terms. Given that $S\_7=7$ and $S\_{15}=75$, let $T\_n$ represent the sum of the first $n$ terms of the sequence $\{ \frac{S\_n}{n} \}$.
(1) Find $a\_1$ and $d$;
(2) Find $T\_n$.

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