Let the first n terms of the sequence {an} and Sn = 2an-2 ^ n 1. Find A3, A4; 2. Prove that: {an + 1-2an} is an equal ratio sequence 3. Find the general formula of {an} [sequence problem] I hope you will give generously and have a detailed process Thank you ~ o (≥ V ≤) O~~

Let the first n terms of the sequence {an} and Sn = 2an-2 ^ n 1. Find A3, A4; 2. Prove that: {an + 1-2an} is an equal ratio sequence 3. Find the general formula of {an} [sequence problem] I hope you will give generously and have a detailed process Thank you ~ o (≥ V ≤) O~~

one
A1=S1=2A1-2^1 A1=2
S2=A1+A2=2A2-2^2 A2=6
S3=S2+A3=2A3-2^3 A3=16
S4=S3+A4=2A4-2^4 A4=40
two
Sn=2An-2^n
S(n+1)=2A(n+1)-2^(n+1)
Subtraction of two formulas
A(n+1)=2A(n+1)-2An-2×2^n+2^n
A(n+1)-2An=2^n
A2-2A1=6-2×2=2
{a (n + 1) - 2An} is an equal ratio sequence
three
An-2A(n-1)=2^(n-1)
An/2^n-A(n-1)/2^(n-1)=1/2
A(n-1)/2^(n-1)-A(n-2)/2^(n-2)=1/2
……
A2/2^2-A1/2^1=1/2
Add the above formula and eliminate the same term
An/2^n-A1/2=(n-1)/2
An=(n+1)/2×2^n=(n+1)×2^(n-1)