Question

Find a formula for the general term a_n of the sequence assuming the pattern of the first few terms continues.

{3, 1, -1, -3, -5, ...}

Assume the first term is a1

a_n=

Answer 1

a(1)=3
d= -2 (can be found 1-3=-2,-5-(-3)=-2)
a(n)=a(1) +d(n-1)
a(n)=3-2(n-1)
a(n)=3-2n+2=5-2n