किस गुणोत्तर श्रेणी में \(a_3=80\) और \(a_6=5120\) है। यदि (r) धनात्मक है, तो \(a_1\) क्या है?
In a geometric progression \(a_3=80\) and \(a_6=5120\). If (r) is positive, what is \(a_1\)?
Explanation opens after your attempt
Correct Answer
B. (5)
Concept
\(\frac{5120}{80}=64=r^3\), so (r=4) and \(a_1=\frac{80}{4^2}=5\). In exams, find (r) first and then the first term.
Why this answer is correct
The correct answer is B. (5). \(\frac{5120}{80}=64=r^3\), so (r=4) and \(a_1=\frac{80}{4^2}=5\). In exams, find (r) first and then the first term.
Exam Tip
\(\frac{5120}{80}=64=r^3\) से (r=4) और \(a_1=\frac{80}{4^2}=5\) है। परीक्षा में पहले (r) निकालें फिर पहला पद।
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