Respuesta :

Show that n is odd →∃m∈ℤ,n2=8m+1

Let k be an integer so that n=2k+1. Then n2=(2k+1)2=4k2+4k+1=2(2k2+2k)+1.


But this isn't equal to 8m+1, so can I change that into 4(2m)+1?