Question

Write a formula for the general term or nth term for the sequence. Then find the indicated term. negative 1​, 1​, 3​, 5​, 7​, ​...; a 11

Answer 1

The given sequence is:

-1, 1, 3, 5, 7, ....

If we observe the sequence, each term is 2 more than the previous term. Since the difference among the terms is common, the sequence is an AP.

The general term of the sequence will be:


`a_(n)= a_(1)+(n-1)d \\ \\ a_(1)= -1 \\ \\ d=2 \\ \\ a_(n)=-1 +(n-1)*2=-1+2n-2=2n-3`

So, the 11th term of the sequence will be:


`a_(11)=2(11)-3=19`