Prove that for each natural number n 26 we have 2n 3 3 2" Use the above to prove that for each na...
Prove by Induction
24.) Prove that for all natural numbers n 2 5, (n+1)! 2n+3 b.) Prove that for all integers n (Hint: First prove the following lemma: If n E Z, n2 6 then then proceed with your proof.
(a) Prove that, for all natural numbers n, 2 + 2 · 2 2 + 3 · 2 3 + ... + n · 2 n = (n − 1)2n+1 + 2. (b) Prove that, for all natural numbers n, 3 + 2 · 3 2 + 3 · 3 3 + ... + n · 3 n = (2n − 1)3n+1 + 3 4 . (c) Prove that, for all natural numbers n, 1 2 + 42 + 72...
Prove or Disprove:
For any natural number n, 7 divides (gn – 2n).
4. Let n be a natural number (a) Prove that -2 ()= ("71). (Hint: consider the cases n 1 and n 2 2 separately.) 3 () (b) Conjecture and prove a similar expression for 3 ()? .n (c) What is
-1) Prove that 12+22 + ... + n2 = n(n + 1) (2n + 1) 6
-1) Prove that 12+22 + ... + n2 = n(n + 1) (2n + 1) 6
3. Use the Division Algorithm (Theorem 6.1.1) to prove that for all n ez+ 6 I n(n +1) (2n +1).
3. Use the Division Algorithm (Theorem 6.1.1) to prove that for all n ez+ 6 I n(n +1) (2n +1).
Exercise 1.6.4: Prove the following by induction: (a) “k - n(n+1)(2n +1) k= 1 (b) If n > 1, then 13-n is divisible by 3. (c) For n 3, we have n +4 <2". (d) For any positive integer n, one of n, n+2, and 11+ 4 must be divisible by 3. (e) For all n e N, we have 3" > 2n +1. ()/Prove that, for any x > -1 and any n e N, we have (1+x)" 21+1x.
(Hammack Problem 5.25) If n N and 2n-1 is prime, then n is prime. Hint: You may assume that 2b-1- (2 1 (201)a +- 2(6-2)a +2+1) for natural numbers 22 and b22
(Hammack Problem 5.25) If n N and 2n-1 is prime, then n is prime. Hint: You may assume that 2b-1- (2 1 (201)a +- 2(6-2)a +2+1) for natural numbers 22 and b22
2n 3. Prove that lim n+on+ 1 2.
Exercise 2.4. Prove the two statements below:Use nd ueTion 1. For every integer n 2 3, the inequality n2 2n +1 holds. Hint: You can prove this by induction if you wish, but alternatively, you can prove directly, without induction.) 2. For every integer n 2 5, the inequality 2" n holds. (Hint: Use induction and the inequality in the previous part of the exercise.)