Prove the following using the principle of mathematical induction for all n ∈ N
1.2 + 2.3 + 3.4 + …+n.(n+1) =
1.3 + 3.5 + 5.7 +…+(2n – 1)(2n + 1)=
1.2 + 2.22 + 3.23 + …+n.2n = (n – 1)2n + 1 + 2
a + ar + ar2 + …+ arn–1 =
12 + 32 + 52 +…+(2n –1)2 =
n (n + 1) (n + 5) is a multiple of 3.
102n – 1 + 1 is divisible by 11.
x2n – y2n is divisible by x + y.
32n + 2 – 8n – 9 is divisible by 8.
41n – 14n is a multiple of 27.
(2n + 7) < (n + 3)2.