VeritasPrepKarishma wrote:
RnH wrote:
One thing that I learned, more like stumbled upon, while preparing was that if you are to square any number, the just multiple the number before and after that number, and then add 1.
i.e. (n-1)*(n+1) + 1 = n^2
i.e. (n-1)*(n+1) + 1 = n^2
Also, think about why it is so.
(n-1)*(n+1) = (n^2 - n + n - 1) = n^2 - 1
Therefore, (n-1)*(n+1) + 1 = n^2 - 1 + 1 = n^2
Exactly! I had problems with higher multiples of 7 and this helped me get over the issue.
