Arithmetic sequence - 1.5 2 19 - 1

Arithmetic sequence - 1.5 2 19 - 1

It is 25. Subtract the last number from the last number to get a new sequence: 3.5 - 18 - 10. Then subtract the last number from the last number to get a new sequence: - 4.59 - 18. This new sequence is an equal ratio sequence with common ratio - 2. Infer that the next one should be 36. Infer that 26 - (0-10) = 36, then 26.25 - (- 1) = 26 after - 10, infer that the original number is 25

It is known that the second term of the arithmetic sequence {an} is 8, and the sum of the first 10 terms is 185. Take the second term, the fourth term and the eighth term from the sequence {an}
A new sequence {BN} is formed by the nth power term of {BN}. The general term formula of {BN} and the sum formula of the first n terms are obtained
Why is BN = 3 × 2 to the nth power + 2? Find the sum of Q and A1. Why is the sum of n terms Sn = 3 (the nth power of 2 + 4 +... + 2) + 2n=
How can we get the N + 1 power of 3 × 2 + 2n-6

Let the tolerance of sequence {an} be D, then: A2 = a1 + D = 8s10 = 10A1 + 45d = 185 simultaneous: D = 3A1 = 5} an = 5 + 3 (n-1) = 3N + 2. According to the meaning of the problem, take out the first n of the sequence {BN} from item 2,4,8., that is: B1 = a2b2 = a4b3 = a8bn = a (2 ^ n)