✔ 最佳答案
教甄數求解:x^2-y^2=101^2之整数解有幾组?
Sol
x^2-y^2=101^2
(x-y)(x+y)=101^2
101為質數
101^2有3個正因數
1,101,101^2
So
101^2=1*10201=101*101
(1) x-y=1,x+y=10201
x=5101,y=5100
(2) x-y=101,x+y=101
x=101,y=0
(3) x-y=10201,x+y=1
x=5101,y=-5100
(4) x-y=-1,x+y=-10201
x=-5101,y=-5100
(5) x-y=-101,x+y=-101
x=-101,y=0
(6) x-y=-10201,x+y=-1
x=-5101,y=5100
共有6組解