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A G.P. consists of 2n terms. If the sum ...

A G.P. consists of 2n terms. If the sum of the terms occupying the odd places is `S_(1)`, and that of the terms in the even places is `S_(2)`, then `S_(2)/S_(1)`, is

A

independent of a

B

independent of r

C

independent of a and r

D

dependent on r

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To solve the problem, we need to find the ratio \( \frac{S_2}{S_1} \) where \( S_1 \) is the sum of the terms in the odd places and \( S_2 \) is the sum of the terms in the even places of a geometric progression (G.P.) consisting of \( 2n \) terms. ### Step-by-Step Solution: 1. **Identify the Terms of the G.P.**: The terms of the G.P. can be expressed as: \[ T_1 = A, \quad T_2 = AR, \quad T_3 = AR^2, \quad \ldots, \quad T_{2n} = AR^{2n-1} \] 2. **Sum of Terms in Odd Places (\( S_1 \))**: The terms in odd places are: \[ T_1, T_3, T_5, \ldots, T_{2n-1} \] This corresponds to: \[ S_1 = A + AR^2 + AR^4 + \ldots + AR^{2n-2} \] This is a geometric series with the first term \( A \) and common ratio \( R^2 \). The number of terms is \( n \). The sum of a geometric series is given by: \[ S_n = a \frac{1 - r^n}{1 - r} \] Applying this formula: \[ S_1 = A \frac{1 - (R^2)^n}{1 - R^2} = A \frac{1 - R^{2n}}{1 - R^2} \] 3. **Sum of Terms in Even Places (\( S_2 \))**: The terms in even places are: \[ T_2, T_4, T_6, \ldots, T_{2n} \] This corresponds to: \[ S_2 = AR + AR^3 + AR^5 + \ldots + AR^{2n-1} \] This is also a geometric series with the first term \( AR \) and common ratio \( R^2 \). The number of terms is \( n \). Thus: \[ S_2 = AR \frac{1 - (R^2)^n}{1 - R^2} = AR \frac{1 - R^{2n}}{1 - R^2} \] 4. **Finding the Ratio \( \frac{S_2}{S_1} \)**: Now, we can find the ratio: \[ \frac{S_2}{S_1} = \frac{AR \frac{1 - R^{2n}}{1 - R^2}}{A \frac{1 - R^{2n}}{1 - R^2}} \] The terms \( A \) and \( \frac{1 - R^{2n}}{1 - R^2} \) cancel out: \[ \frac{S_2}{S_1} = R \] ### Conclusion: Thus, the final result is: \[ \frac{S_2}{S_1} = R \]

To solve the problem, we need to find the ratio \( \frac{S_2}{S_1} \) where \( S_1 \) is the sum of the terms in the odd places and \( S_2 \) is the sum of the terms in the even places of a geometric progression (G.P.) consisting of \( 2n \) terms. ### Step-by-Step Solution: 1. **Identify the Terms of the G.P.**: The terms of the G.P. can be expressed as: \[ T_1 = A, \quad T_2 = AR, \quad T_3 = AR^2, \quad \ldots, \quad T_{2n} = AR^{2n-1} ...
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OBJECTIVE RD SHARMA ENGLISH-SEQUENCES AND SERIES-Chapter Test
  1. A G.P. consists of 2n terms. If the sum of the terms occupying the odd...

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  2. Let H(n)=1+(1)/(2)+(1)/(3)+ . . . . .+(1)/(n), then the sum to n terms...

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  3. Sum of the first n terms of the series 1/2+3/4+7/8+(15)/(16)+............

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  4. If A(1),A(2) are between two numbers, then (A(1)+A(2))/(H(1)+H(2)) is ...

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  5. If the (m+1)t h ,(n+1)t h ,a n d(r+1)t h terms of an A.P., are in G.P....

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  6. Given that n arithmetic means are inserted between two sets of numbers...

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  7. If a,b, and c are in G.P then a+b,2b and b+ c are in

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  8. If in a progression a1, a2, a3, e t cdot,(ar-a(r+1)) bears a constant...

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  9. If in an AP, t1 = log10 a, t(n+1) = log10 b and t(2n+1) = log10 c then...

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  10. Find the sum of the series: 1^2-2^2+3^2-4^2+.....-2008^2+2009^2.

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  11. If 4a^(2)+9b^(2)+16c^(2)=2(3ab+6bc+4ca)," where "a,b,c are non-zero nu...

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  12. If Sn denotes the sum of n terms of an A.P. whose common difference is...

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  13. The sides of a right angled triangle are in A.P., then they are in the...

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  14. Find the sum of all the 11 terms of an AP whose middle most term is 30...

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  15. The maximum sum of the series 20+19 1/3+18 2/3+ is 310 b. 300 c. 0320 ...

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  16. If three numbers are in G.P., then the numbers obtained by adding the ...

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  17. If p ,q ,r are in A.P., show that the pth, qth and rth terms of any G....

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  18. Let a,b,c be three positive prime number. The progrrssion in which sqr...

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  19. If 1/(b-a)+1/(b-c)=1/a+1/c , then (A). a ,b ,a n dc are in H.P. (B). a...

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  20. If three numbers are in H.P., then the numbers obtained by subtracting...

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  21. The first three of four given numbers are in G.P. and their last three...

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