Question 1 Report
The second term of a geometric progression is 3. If its sum to infinity is \(\frac{25}{2}\), find the value of its common ratio.
Let the first term be \(a\) and common ratio \(r\), with \(|r| < 1\).
Second term: \(ar = 3\), so \(a = \dfrac{3}{r}\).
Sum to infinity: \(\dfrac{a}{1 - r} = \dfrac{25}{2}\). Substitute \(a\):
Solve:
Both satisfy \(|r| < 1\), so the common ratio is \(r = \dfrac{3}{5}\) or \(r = \dfrac{2}{5}\).
Answer Details
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