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For each positive integer n, the quantity sn is defined such that sn

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Sajjad1994
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For each positive integer n, the quantity sn is defined such that sn [#permalink] New post  14 May 2020, 01:02
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Question # 239, Date : 28-May-2020
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For each positive integer n, the quantity \(s_{n}\) is defined such that \(s_{n + 2} = (s_{n})^2 − s_{n + 1}\). In addition, \(s_{2} = 1\).

Select values for \(s_{1}\) and \(s_{4}\) that are jointly compatible with these conditions. Make only two selections, one in each column.

\(s_{1}\)\(s_{4}\)Values
-12
-7
-3
-1
0


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\(s_{1}= -3\)
\(s_{4}= -7\)
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Re: For each positive integer n, the quantity sn is defined such that sn [#permalink] New post  25 Aug 2021, 08:46
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Re: For each positive integer n, the quantity sn is defined such that sn [#permalink] New post  Updated on: 14 May 2020, 23:00
S1 and S4 are related with relation --->

S1(sq2) + S4 = 2

Originally posted by ashwani1984 on 14 May 2020, 01:39.
Last edited by ashwani1984 on 14 May 2020, 23:00, edited 1 time in total.
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Re: For each positive integer n, the quantity sn is defined such that sn [#permalink] New post  14 May 2020, 07:59
Given: sn+2=(sn)2−sn+1
S2 = 1.

When we substitute values for S3 and S4 we get:
S3 = S1^2 - S2.
S4 = S2^1 - S3 => S4 = S2^1 - S1^2 + S2,
Now Substituting S2 =1, we get:
S4 + S1^2 = 2.

Only 2 values satisfy the given condition: S4 = -7, S1 = -3
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Re: For each positive integer n, the quantity sn is defined such that sn [#permalink] New post  14 May 2020, 12:39
Here,

S3= S1^2-S2
S4=S2^2-S3
S4= S2^2-S1^2+S2
Now S2=1
S4=2-S1^2
So checking from options

S4=-7,S1=-3

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Re: For each positive integer n, the quantity sn is defined such that sn [#permalink] New post  29 May 2020, 18:53
S4= s2^2-S3
S3=s1^2-1

S4 = s2^2-s1^2+1
S4= 2-s1^2


Values are given in negative it means s4 could be negative it means s1 mode should be higher than 2
Try s1= -3
S2 comes out to be -7
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Re: For each positive integer,the quantity [size=150]S[/size]n i [#permalink] New post  16 Sep 2022, 05:58
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Re: For each positive integer,the quantity [size=150]S[/size]n i [#permalink]
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