ta có : [TEX]x^3+x^2+x+1=(2y+1)^2[/tex]
<=>[tex](x+1)(x^2+1)=(2y+1)^2[/tex]
[tex](x+1;x^2+1)=d[/tex]
=>d=1 or d=2
vi [tex](2y+1)^2[/tex] le nen d=1 hay [tex]x+1;x^2+1 [/tex]nguyen to cung nhau
ma tich cua no la so chinh phuong nen
TH1:ca 2 so deu la so chinh phuong
TH2:1 trong 2 so =0