Geometric Series Perfect Square
Consider the geometric series $ 4+\frac{12}{a}+\frac{36}{a^2}+\cdots $. If the sum is a perfect square, what is the smallest possible value of $ a $ where $ a $ is a positive integer?
- 1
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- 3
- +
- 4
- 5
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- -
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- 9
- $\frac{a}{b}$
- .
- 0
- =
- %
- $a^n$
- $a^{\circ}$
- $a_n$
- $\sqrt{}$
- $\sqrt[n]{}$
- $\pi$
- $\ln{}$
- $\log$
- $\theta$
- $\sin{}$
- $\cos{}$
- $\tan{}$
- $($
- $)$
- $[$
- $]$
- $\cap$
- $\cup$
- $,$
- $\infty$