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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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