Question

$thepersonwhoanswerswillget100points$
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Answer 1

Answer:

$a \: = \frac{ - 5 + 3 \sqrt{5} }{2}$

or

$a \: = \frac{ - 5 - 3 \sqrt{5} }{2}$

As it is th positive addition of infinite terms , you can consider the first value of 'a'.