Let α and β be the roots of the equation, 5 x 2 + 6 x - 2 = 0 . If S n = α n + β n ,…

Let α and β be the roots of the equation, 5x2+6x-2=0. If Sn=αn+βn, n=1, 2, 3, ...., then
  1. 6S6+5S5=2S4
  2. 5S6+6S5+2S4=0
  3. 5S6+6S5=2S4
  4. 6S6+5S5+2S4=0

Solution

If α, β are roots of quadratic equation 5x2+6x-2=0

 5α2+6α-2=0 5α2+6α=2

 5β2+6β-2=0 5β2+6β=2

5S6+6S5=5α6+β6+6α5+β5

=α45α2+6α+β45β2+6β

=2α4+β4=2S4

Asked in: JEE Main 2020 (02 Sep Shift 1)

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