Senior one mathematics compulsory 5, find the general formula In the sequence {an}, if A1 = 1 and an + 1 = 2An + 3, then the general term an of the sequence= Ask the master to give the answer, and give the steps!

Senior one mathematics compulsory 5, find the general formula In the sequence {an}, if A1 = 1 and an + 1 = 2An + 3, then the general term an of the sequence= Ask the master to give the answer, and give the steps!

From a (n + 1) = 2An + 3, we can get a (n + 1) + 3 = 2 (an + 3), that is {a (n + 1) + 3} / (an + 3) = 2. Thus we can know that the sequence {(an + 3)} is an equal ratio sequence with a common ratio of 2. Then (an + 3) = (a1 + 3) * 2 ^ (n-1) = 4 * 2 ^ (n-1) = 2 ^ (n + 1), so the problem of an = 2 ^ (n + 1) - 3 is to construct