Q82.Let a1, a2, a3, … be an A.P. If ∑∞r=1 ar2r = 4, then 4a2 is equal to ______.
What This Question Tests
This question tests the ability to sum an infinite arithmetico-geometric progression, which typically involves recognizing patterns and using a standard formula or the method of differentiation.
Concepts Tested
Formulas Used
Sum of A.G.P. S = a/(1-r) + dr/(1-r)²
General term of AP: a_n = a_1 + (n-1)d
📚 NCERT Sections This Tests
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2.2 A regular hexagon of side 10 cm has a charge 5 mC at each of its vertices. Calculate the potential at the centre of the hexagon.
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8.17 Complete each synthesis by giving missing starting material, reagent or products
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2.1 Two charges 5 × 10–8 C and –3 × 10–8 C are located 16 cm apart. At what point(s) on the line joining the two charges is the electric potential zero? Take the potential at infinity to be zero.
📋 Question Details
- Chapter
- Sequences & Series
- Topic
- Arithmetic Progression, Sum of Infinite Series
- Year
- 2022
- Shift
- 29 Jul Shift 1
- Q Number
- Q82
- Type
- Numerical
- NCERT Ref
- Class 11 Mathematics Ch 9: Sequences and Series
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