JEE Main 2020 — Definite Integration Question with Solution
From: JEE Main 2020 (Online) 4th September Evening Slot
Question
Let {x} and [x] denote the fractional part of x and
the greatest integer x respectively of a real
number x. If and 10(n2 – n),
are three consecutive terms of a G.P., then n is equal to_____.
the greatest integer x respectively of a real
number x. If and 10(n2 – n),
are three consecutive terms of a G.P., then n is equal to_____.
Enter your answer
Show full solutionCorrect answer: 21
Correct answer
21
Step-by-step explanation
[As period of {x} = 1]
= 1 + 2 + 3 + ....+ (n - 1)
=
As , , 10(n2 – n) are in GP.
n2 = 21n
n = 21
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