It is known that the arithmetic sequence an satisfies A2 = 2, A5 = 8, 1. Find the general term formula 2 of the sequence an. Let the sum of the first n terms of the arithmetic sequence BN with all positive numbers be TN. if B3 = A3, T3 = 7, find TN

It is known that the arithmetic sequence an satisfies A2 = 2, A5 = 8, 1. Find the general term formula 2 of the sequence an. Let the sum of the first n terms of the arithmetic sequence BN with all positive numbers be TN. if B3 = A3, T3 = 7, find TN

1、
a5-a2=3d=6
d=2
a1=a2-d=0
an=0+2(n-1)
So an = 2n-2
2、
b3=a3=2*3-2=4
T3=b1+b2+b3=7
b1+b2=3
b1+b1*q=3
b1(1+q)=3
b3=b1*q²=4
be divided by
q²/(1+q)=4/3
3q²-4q-4=0
(q-2)(3q+2)=0
All items are positive
So Q > 0
q=2
b1(1+q)=3
b1=1
So BN = 2 ^ (n-1)

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write the following in algebraic form .
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Well
Is it
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