A-Level Maths: D2-01 Sequences: GCSE Revision on Linear and Quadratic Sequences

[ninanakagawa]

i'm gonna share this awesome lesson !!

[MathBuz]

After we calculate the values of n^2 then we write down
n^2 = 1, 4, 9, 16, 25, ....
From here we can solve it other way round..
Now we subtract the Original terms minus the values of n^2, we get
1, -1, -3, -5, -7, ....
here the difference of terms is -2, and its nth term is -2n + 3
Now we can add -2n +3 to n^2 i.e.
n^2 -2n +3 is the required nth term.

I have a question that its ok if we use any of the two ways or your method is more suitable?