Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NDA2022MathematicsMathematical InductionActual

Consider the following statements : 1. 2+4+6+ +2 n=n^2+n 2. The expression n^2+n+41 always gives a prime number for every natural number n Which of the above statements is/are correct?

Options

  1. A1 only
  2. B2 only
  3. CBoth 1 and 2
  4. DNeither 1 nor 2

Correct answer

A. 1 only

Step-by-step solution

Let S=2+4+6+ +2 n=2(1+2+3+ +n)=2 n(n+1) 2 =n^2+n Statement 1 is true. Putting n=41 in n^2+n+41=41^2+41+41=41 .(41+2)=41.43 Which is not prime. So, expression not always prime for n N

Practice Mathematical Induction on Quantrex Academy →

More from Mathematical Induction

For all n ~N , 2^ 4 n -15 n-1 is divisible by 2011 Full Mathematical Induction list All NDA PYQs