# Math Help - need help with a proof

1. ## need help with a proof

use a direct proof to show that every odd integer is the difference of two squares.

i dont understand how the solution defines ((k+1)^2)-(k^2) = n
from (n = 2K+1)

where does the (k+1)^2 and the k^2 come from?

2. Originally Posted by camboguy
use a direct proof to show that every odd integer is the difference of two squares.

i dont understand how the solution defines ((k+1)^2)-(k^2) = n
from (n = 2K+1)

where does the (k+1)^2 and the k^2 come from?
$(x+1)^2=x^2+2x+1$