Question

Find the first three terms of the sequence sum of the nth term=n²(n+1)/4​

Answer 1

Answer:

The sum of the first n terms of a sequence is given by Sn = n(n+2). Can you find the first three terms of the sequence?

Start with S1 = 1*(1+2) = 1*3 = 3. So the first term is 3.

Next, S2 = 2(2+2) = 2*4 = 8. This the sum of the first two terms. Since the first term is 3, the second term is 8–3 = 5.

Next, S3 = 3(3+2) = 3*5 = 15. This the sum of the first three terms. Since the sum of the first two terms is 8, the third term is 15–8 = 7.

Hence the first three terms are: 3, 5, and 7