Question

Find the sum of n terms of the series whose nth term as (2n-1)2 ?

Answer 1

tn = (2n-1)2
t₁ = 2
t₂ = 6
t₃=10
the series is in a.p.
d=4
a=2
sum of n terms of ap =n/2 [ 2a+(n-1)d ]
                              =n/2  [ 4+ 4n-4 ]
                              =n/2 [ 4n ]
                              =4n²/2
                              =2n²

Answer 2

tn = (2n-1)2
t₁ = 2
t₂ = 6
t₃=10
the series is in a.p.
d=4
a=2
sum of n terms of ap =n/2 [ 2a+(n-1)d ]
                              =n/2  [ 4+ 4n-4 ]
                              =n/2 [ 4n ]
                              =4n²/2
                              =2n² 
                              =2n*2n
                              =4n