JEE Previous Year Question
The number of elements in the set {n Z :| - 10n + 19|< 6} is_______.
Topic: JEE PYQ
Answer: 6. Full step-by-step solution below.
Correct answer: 6
Solution
(6)Given,
|n2-10n + 19| < 6
Now we know that,
|x|a -a < x < a
Now using above formula, we get,
-6 < n2 - 10n + 19 < 6
n2 -10n + 25 > 0 and n2 - 10n + 13 < 0
(n-5)2 > 0 and (n-(5 - 2)) (n-(5 + 2)) < 0
and n{2, 3,4, 5, 6, 7, 8}
Hence, n = 2, 3, 4, 6, 7, 8