Let the 10th term of the arithmetic sequence an be 23 and the 25th term be - 22, and find the sum of the absolute values of the first 50 terms of the arithmetic sequence an

Let the 10th term of the arithmetic sequence an be 23 and the 25th term be - 22, and find the sum of the absolute values of the first 50 terms of the arithmetic sequence an

d=(a25-a10)/(25-10)=-3
an=a10+(n-10)d=23-3(n-10)=53-3n
a1=50
Let an > = 0,53-3n > = 0, N0, A18

4, 2, 6, 8, 14, 22, what are the following two numbers!

4 + 2 = 6 2 + 6 = 8 6 + 8 = 14 8 + 14 = 22 14 + 22 = 36 36 + 22 = 58 this is the procedure

1. 2, 4, 8, 14, 22... Find the nth number
2. Other examples of a + B = C, a · B = C, dividing a = 2, B = 2 or a = 3, B = 1.5

The first questions 1 and 2 are special cases. Starting from the third number, 4 = 2 ^ 2-08 = 3 ^ 2-114 = 4 ^ 2-222 = 5 ^ 2-3 Let the nth number be mm = (n-1) ^ 2 - (n-3) = n ^ 2-3n + 4, so when n = 1, M = 1n = 2, M = 2n > = 3, M = n ^ 2-3n + 4. Another way is to see the difference 2-1 = 1 (special case) 4-2 = 28-4 = 414-8 = 622

2.4.8.14.22.

32,44,58