Question

If Tn=n²-1, find Tn-1 and Tn+1

Answer 1

Tn = n²-1

Tn-1 = (n-1)² - 1

= n²+1-2n -1

= n²-2n

= n(n-2). answer

now

Tn+1= (n+1)² -1

= n²+2n+1-1

= n²+2n

= n(n+2) answer

Answer 2

Tn+1= n^2

and Tn-1=(n^2)-2

so simple