Question

Find the first four terms of the sequence given a1=−9 and an+1=an+n.

Answer 1

Correction in question:

Find the first four terms of the sequence given a1 = −9 and an + 1 = a + n.

Answer

a = -9

an + 1 = a + n

=> an = a + n - 1

=> a2 = -9 + 2 - 1

=> a2 = -8

d = a2 - a = 1

Terms = -9, -8, -7, -6...