Question

The sum of n terms of an ap is 2n+3n2 determine ap find the 10 term

Answer 1

Sn = 3n²+2n
S1 = a1 = 3+2 = 5

Now a2= S2-S1 thus
a2 = 16-5 = 11

Now a2-a1 = common difference = d

So d = 6

Now
An = a+(n-1)d
An = 5+(n-1)6

ATQ
A10 = 5+(9)6 = 5+54 => 59
So tenth term is 59.