Sn= N^2-4n, using this formula find the first 4 terms
n = 1 , S(1) = 1 - 4 = -3
n= 2, S(2) = 4 - 8 = -4
n = 3, S(3) = 9 - 12 = -3
n = 4, S(4) = 16 - 16 = 0
term(1) = -3
term(2) = sum(2) - sum(1) = -4-(-3) = -1
term(3) = sum(3) - sum(2) = -3 -(-4) = 1
term(4) = sum(4) - sum(3) = 0 -(-3) = 3
so the first 4 terms are -3, -1, 1, 3
looks like an AS with a = -3 and d = 2
To find the first four terms of the sequence Sn = N^2-4n, we can substitute the first four positive integers (N = 1, 2, 3, 4) into the formula:
For N = 1:
S1 = (1^2) - 4(1) = 1 - 4 = -3
For N = 2:
S2 = (2^2) - 4(2) = 4 - 8 = -4
For N = 3:
S3 = (3^2) - 4(3) = 9 - 12 = -3
For N = 4:
S4 = (4^2) - 4(4) = 16 - 16 = 0
Therefore, the first four terms of the sequence Sn = N^2-4n are: -3, -4, -3, 0.
To find the first four terms of the given sequence Sn = N^2 - 4n, we need to substitute the values of N from 1 to 4 into the formula and calculate the corresponding terms.
Let's start by substituting N = 1 into the formula:
S1 = (1)^2 - 4(1) = 1 - 4 = -3
Next, substitute N = 2:
S2 = (2)^2 - 4(2) = 4 - 8 = -4
Then, substitute N = 3:
S3 = (3)^2 - 4(3) = 9 - 12 = -3
Lastly, substitute N = 4:
S4 = (4)^2 - 4(4) = 16 - 16 = 0
Therefore, the first four terms of the sequence are: -3, -4, -3, 0.