neu co so tu nhien n sao cho k =n^2 thi ta noi so k la so chinh phuong tim tat ca cac so ab saocho (ab+ba) la so chinh phuong
cho x =(2n + 1)(3n+2) voi n thuoc N*
hoi tich tat ca cac uoc cua x co phai la so chinh phuong khong? giai thich?
tim tat ca cac so nguyen duong x,y sao cho cac so x2+3.y va y2+3.x deu la so chinh phuong cua 1 so
tim tat ca cac so nguyen to p sao cho 5^p+12^p la so chinh phuong
tim tat ca cac stn>9 sao cho khi xoa di cs hang dv cua no thi dc so moi la uoc cua chinh so do
tim cac stn n de Q=1!+2!+3!+....+n! la mot so chinh phuong.
tim stn n khac 0 sao cho : 1!+2!+3!+....+n! la 1 so chinh phuong
tim stn n khac 0 sao cho : 1!+2!+3!+....+n! la 1 so chinh phuong
Tim stn n có 2 chu so sao cho 2n la binh phuong cua 1 stn,3n la lap phuong cua mot stn
