Suppose S is a statement about n for each n 1. Explain what must be done

Question:

Suppose S" is a statement about n for each n ≥ 1. Explain what must be done to prove that Sn is true for all n ≥ 1 if it is known that
(a) Sn ⇒ Sn+2 for each n ≥ 1.
(b) Sn ⇒ Sn+8 for each n ≥ 1.
(c) Sn ⇒ Sn+1 for each n ≥ 10.
(d) Both Sn and Sn+i ⇒ Sn+2 for each n ≥ 1.