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In a sequence of (4n+1) terms, the first...

In a sequence of `(4n+1)` terms, the first `(2n+1)` terms are n A.P. whose common difference is 2, and the last `(2n+1)` terms are in G.P. whose common ratio is 0.5 if the middle terms of the A.P. and LG.P. are equal ,then the middle terms of the sequence is `(n .2 n+1)/(2^(2n)-1)` b. `(n .2 n+1)/(2^n-1)` c. `n .2^n` d. none of these

A

`(n.2^(n+1))/(2^(n)-1)`

B

`(n.2^(n+1))/(2^(2n-1))`

C

`n.2^(n)`

D

none of these

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A
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FIITJEE-PROGRESSION & SERIES -ASSIGNMENT PROBLEMS (OBJECTIVE) LEVEL-I
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  2. If the sequences 1,2,2,4,4,4,4,8,8,8,8,8,8,8,8….. where n consecutive ...

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  3. If S(r)= sum(r=1)^(n)T(1)=n(n+1)(n+2)(n+3) then sum(r=1)^(10) 1/(T(r))...

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  4. a,b,c,d,e are five numbers in which the first three are in A.P and th...

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  5. The coefficient of x^15 in the product (1-x)(1-2x) (L-2^2 x) (L-2^3 ...

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  6. Sum of n terms of the series (2n-1)+2(2n-3)+3(2n-5)+... is

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  7. The sum of n terms of the series 5/(1.2). 1/3 +7/(2.3). 1/(3^(2))+9/(...

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  8. Let tr=2^(r/2)+2^(-r/2) then sum(r=1)^10 tr^2=

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  9. In a sequence of (4n+1) terms, the first (2n+1) terms are n A.P. whose...

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  10. Let a(1),a(2),a(3),a(4),a(5) be a five term geometric sequence satisfi...

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  11. The nth term of the series 10,23,60,169,494 , …….. is

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  12. The value of sum(n=0)^(m) log ((a^(2n-1))/(b^(m-1)))(a != 0 , 1 , b ...

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  13. A , r = 1 , 2, 3 ….., n are n points on the parabola y^(2)=4x in the...

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  14. Sum to n terms of the series 1^(3) - (1.5)^(3) +2^(3)-(2.5)^(3) +…. is

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  15. Find the sum of the product of every pair of the first n of natural n...

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  16. in the given square, a diagonal is drawn, and parallel line segments j...

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  17. For the series 21,22,23 ,….. K - 1 , k the G,M of the first and las...

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  18. If a1, a2, a3, an are in H.P. and f(k)=(sum(r=1)^n ar)-ak ,t h e n (a...

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  19. Statement 1 : If x , y , z are positive and x+y + z= 1 , then (1/x -...

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  20. Statemnet 1 : If three positive unequal numbers a,b,c are in H.P th...

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