Question

The sum of first n terms of an ap is 5 m square minus n square find the end term

Answer 1

Sn = 5m^2 - n

S(n - 1) = 5m^2 - (n -1)

S(n - 1) = 5m^2 - n + 1

an = Sn - Sn - 1

an = 5m^2 - n - (5m^2 - n + 1)

an = 5m^2 - n - 5m^2 + n - 1

an = -1

So the end term is -1 .