Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
2n<n! is true for where nN
MathematicsMathematical InductionJEE Main
Options:
  • A n<4
  • B n4
  • C n<3
  • D None of these
Solution:
1148 Upvotes Verified Answer
The correct answer is: n4
P n  : 2n<n !

P 1 ,P 2 ,P 3 are not true.

P 4  : 16<24  is true

P K : K!>2K is true for some KN, K>4

To prove P(K+1)K+1!>2K+1 is true

Multiplying both sides of P K by (K+1), we get,

K+1!>2KK+1>2K.2(as  K>4)

Hence by PMI, P n is true  nN,  n4

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.