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Let a1,a2,a3…… ,an be in G.P such that ...

Let `a_1,a_2,a_3…… ,a_n ` be in G.P such that `3a_1+7a_2 +3a_3-4a_5=0` Then common ratio of G.P can be

A

2

B

`3/2`

C

`5/2`

D

`-1/2`

Text Solution

Verified by Experts

The correct Answer is:
B, D

Given
`3a_(1)+7a_(2)+3a_(3)-4a_(5)=0`
`rArr7(a_(1)+a_(2)+a_(3))=4(a_(1)+a_(3)+a_(5))`
`rArr7(1+r+r^(2))=4(1+r^(2)+r^(4))`
`rArr7=4(r^(2)-r+1)`
`rArr4r^(2)-4r+1=4`
`rArr(2r-1)^(2)=4`
`rArr2r-1=pm2`
`rArrr=3//2,-1//2`
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CENGAGE-PROGRESSION AND SERIES-Exercise (Multiple & Comprehension)
  1. If sum of an indinite G.P p,1,1//p,1//p^2…=9/2.. Is then value of p is

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  2. The tems of an infinitely decreasing decreasing G.P having common rati...

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  3. Let a1,a2,a3…… ,an be in G.P such that 3a1+7a2 +3a3-4a5=0 Then common...

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  4. If p(x)=(1+x^2+x^4++x)/(1+x+x^2++x^(n-1)^(2n-2) is a polynomial in x ,...

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  5. If n >1 , the value of the positive integer m for which n^m+1 divides ...

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  6. The next term of the G.P. x ,x^2+2,a n dx^3+10 is (729)/(16) b. 6 c. 0...

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  7. If 1+2x +3x^2+4x^3 +…..oo ge 4 then

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  8. Let S1, S2, be squares such that for each ngeq1, the length of a side...

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  9. If a, b and c are in G.P and x and y, respectively , be arithmetic mea...

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  10. Consider a sequence {an} with a1=2 & an =(a(n-1)^2)/(a(n-2)) for all ...

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  11. The numbers 1, 4, 16 can be three terms (not necessarily consecutive) ...

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  12. The sum of an infinite geometric series is 162 and the sum of its firs...

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  13. If 1/a,1/b,1/c are in A.P and a,b -2c, are in G.P where a,b,c are non-...

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  14. Sum of an infinite G.P is 2 and sum of its two terms is 1.If its secon...

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  15. For 0 lt phi lt pi//2 , if x =Sigma(n=0)^(oo) cos^(2n) phi ,y=Sigma(n...

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  16. For the series, S=1 +(1)/(1+3)(1+2)^2+(1)/((1+3+5))(1+2+3)^2+(1)/((1...

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  17. If Sigma(r=1)^(n) r(r+1)(2r +3)=an^4+bn^3+cn^2+dn +e then

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  18. If Sn=1^2-2^2+3^2-4^2+5^2-6^2+ ,t h e n S(40)=-820 b. S(2n)> S(2n+2) ...

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  19. 1/(sqrt(2)+sqrt(5))+1/(sqrt(5)+sqrt(8))+1/(sqrt(8)+sqrt(11))+ n terms ...

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  20. Given that x+y+z =15 when a,x,y,z,b are in A.P and 1/x+1/y+1/z=5/3 whe...

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