the sum of the first n terms of an AP is given by sn=3n2-n , determine the AP and its 25thterm.
Dear Student!
Given, sum of first n terms of an AP, Sn = 3n2 – n
Sn = 3n2 – n
Replacing n by n – 1, we get
Let the nth term of AP be an.
Putting n = 25, we get
a25 = 6 × 25 – 4 = 150 – 4 = 146
Thus, the 25th term of the given A.P. is 146.
Cheers!