Q66.The sum of the first 20 terms of the series 1 + 23 + 47 + 158 + 1631 + โฆ is (1) 39 + 1 (2) 38 + 1 219 220 (3) 38 + 1 (4) 39 + 1 219 220 is
What This Question Tests
This question tests the ability to recognize a complex pattern in a series that can be rewritten to reveal a geometric progression, whose sum then needs to be calculated for a specified number of terms.
Concepts Tested
Formulas Used
Sum of G.P. S_n = a(r^n - 1)/(r - 1)
๐ NCERT Sections This Tests
13.4 โ Obtain Approximately The Ratio Of The Nuclear Radii Of The Gold Isotope
Physics Class 12 ยท Chapter 13
13.4 Obtain approximately the ratio of the nuclear radii of the gold isotope 197 79 Au and the silver isotope 10747 Ag .
2.2 โ A Regular Hexagon Of Side 10 Cm Has A Charge 5 Mc At Each Of Its
Physics Class 11 ยท Chapter 2
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.
1.18 โ A Point Charge Of 2.0 Mc Is At The Centre Of A Cubic Gaussian
Physics Class 11 ยท Chapter 1
1.18 A point charge of 2.0 mC is at the centre of a cubic Gaussian surface 9.0 cm on edge. What is the net electric flux through the surface?
๐ Question Details
- Chapter
- Sequences & Series
- Topic
- Sum of series
- Year
- 2018
- Shift
- 16 Apr Online
- Q Number
- Q66
- Type
- MCQ
- NCERT Ref
- Class 11 Mathematics Ch 9: Sequences and Series
More from this Chapter
Q86.In a geometric progression consisting of positive terms, each term equals the sum of the next two terms. Then the common ratio of this progression equals (1) 1 2 (1 โโ5) (2) 21 โ5 (3) โ5 (4) 12 (โ5 โ1)
Q88.The sum of the series 2! 1 โ13! + 4!1 โโฆ upto infinity is (1) eโ2 (2) eโ1 (3) eโ1/2 (4) e1/2
Q71.Statement - 1: For every natural number n โฅ2, 1 + 1 + โฆ + 1 > โn. Statement โ2 : For every โ1 โ2 โn natural number n โฅ2, โn(n + 1) < n + 1. (1) Statement โ1 is false, Statement โ2 is true (2) Statement โ1 is true, Statement โ2 is true, Statement โ2 is a correct explanation for Statement โ1 (3) Statement โ1 is true, Statement โ2 is true; (4) Statement โ1 is true, Statement โ2 is false. Statement โ2 is not a correct explanation for Statement โ1.
Q76.The first two terms of a geometric progression add up to 12. The sum of the third and the fourth terms is 48. If the terms of the geometric progression are alternately positive and negative, then the first term is (1) โ4 (2) โ12 (3) 12 (4) 4