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QJEEM20Ma33ee: JEE Main 2020 Mathematics - Class 11 JEEM20Ma33ee Solution: Let and be the roots of the equation 5x 2 + 6x – 2 = 0. If S n…
Let and be the roots of the equation
5x2 + 6x – 2 = 0. If Sn = n + n, n = 1, 2, 3...., then :
5x2 + 6x – 2 = 0. If Sn = n + n, n = 1, 2, 3...., then :
Multiple Choice Options
- A 5S6 + 6S5 = 2S4
- B 5S6 + 6S5 + 2S4 = 0
- C 6S6 + 5S5 + 2S4 = 0
- D 6S6 + 5S5 = 2S4
Step-by-Step Verified Solution
and be the roots of the equation
5x2 + 6x – 2 = 0.
5 2 + 6 - 2 = 0
5 n + 2 + 6 n + 2 - 2 n = 0 ......(1)
(By multiplying n)
Similarly 5 n + 2 + 6 n + 2 - 2 n = 0 ......(2)
By adding (1) & (2)
5Sn+2 + 6Sn+1 – 2Sn = 0
For n = 4
5S6 + 6S5 = 2S4
5x2 + 6x – 2 = 0.
5 2 + 6 - 2 = 0
5 n + 2 + 6 n + 2 - 2 n = 0 ......(1)
(By multiplying n)
Similarly 5 n + 2 + 6 n + 2 - 2 n = 0 ......(2)
By adding (1) & (2)
5Sn+2 + 6Sn+1 – 2Sn = 0
For n = 4
5S6 + 6S5 = 2S4