已知x=根号3+1y=根号3-1求x方+2xy+y方和x方—y方
x方+2xy+y方
=(x+y)²
=(√3+1+√3-1)²
=(2√3)²
=12

x方—y方
=(x+y)(x-y)
==(√3+1+√3-1)(√3+1-√3+1)
=4√3