Question

若x＝√2＋1＝√2－1 求x²－y²分之x²-3xy=y²的值

Answer 1

x=√2＋1,y=√2－1

x²－y²

=(√2+1)^2-(√2-1)^2

=4√2

x²-3xy+y²

(x-y)^2-xy

=4-1

=3

(x²-y²)/(x²-3xy+y²)

=4√2/3