यदि गुणोत्तर श्रेढ़ी में \(a_1=2\) और \(a_5=162\) है, तथा अनुपात धनात्मक है, तो (r) क्या है?
If a geometric progression has \(a_1=2\) and \(a_5=162\), and the ratio is positive, what is (r)?
Explanation opens after your attempt
Correct Answer
B. (3)
Concept
\(a_5=a_1r^4\), so \(162=2r^4\) and \(r^4=81\), hence (r=3). The position gap decides the exponent.
Why this answer is correct
The correct answer is B. (3). \(a_5=a_1r^4\), so \(162=2r^4\) and \(r^4=81\), hence (r=3). The position gap decides the exponent.
Exam Tip
\(a_5=a_1r^4\), इसलिए \(162=2r^4\) और \(r^4=81\), अतः (r=3)। पद-संख्या का अंतर घात तय करता है।
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