Question

if the sum of the first n ​

Answer 1

Sum of n terms = 4n - n²

Now,

The first term = 4(1) - (1)² = 4-1 = 3

Now ,

Sum of first two terms of AP = 4(2)- (2)²
= 8-4 = 4

So,

Second term of AP = 4-3 = 1


Now ,

Common difference = 1-4 = (-3)

Now,

If sum of n terms = 4n - n²

So,
Sum of first (n-1) terms will be

= 4(n-1) - (n-1)²
= 4n - 4 - n²-1 +2n
= - n²+6n-5

Now ,

The n th term will be as follows :-

=4n - n² +n²-6n+5
= 5-2n


So

The n th term of the AP will be (5-2n)