
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
Given that the sum of the first $n$ terms, $S_n$, of a sequence ${a_n}$ satisfies $S_n=\frac{1}{2}(1-a_n)$.
1. Find the general formula for the terms of the sequence.
2. Let $f(x)=\log_{\frac{1}{3}}x$, $b_n=f(a_1)+f(a_2)+...+f(a_n)$, find the value of $T_n=\frac{1}{b_1}+\frac{1}{b_2}+\frac{1}{b_3}+...+\frac{1}{b_n}$.

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