Problem 2 Use mathematical induction to prove If n is a nonn
Problem 2: Use mathematical induction to prove:
If n is a nonnegative integer, then 2n > n
Use the following steps:
(i) prove that P(0) is true.
(ii) Suppose k>=0. Prove that P(k) is true implies P(k+1) is true.
Suppose P(k) is true, write down P(k) here:
Write down P(k+1) here:
Assuming that P(k) is true, show P(k+1) is true:
Hint: start with:
2k+1 = 2 (2k)
Be sure to use that P(k) is true
Solution
we have to prove p(n) = 2n > n
p(0) = 20 >0 = 1 > 0
p(1) = 21 >1 = 2 >1
since p(0) is true and p(1) is also true
therefore p(k) is true
p(k) = 2k > k.................eqn.{1}
and we have to prove that p(k+1) is true
multiplying both sides by 2 in eqn 1
p(k) = 2 x 2k > 2k
p(k) = 2k+1 > k+k
p(k) = 2k+1 > k+1 .....................{ k>1 }
p(k) can be written as p(k+1)
p(k+1) = 2k+1 > k+k
we have proved p(k+1) is true
therefore it is true for all values of k
