Question

(1-根号2)的平方的算术平方根

Answer 1

(1-根号2)的平方的算术平方根是 √2-1

x=4/(√5-1)

=4(√5+1)/(√5-1)(√5+1)

=4(√5+1)/(5-1)

=√5+1

x²-2x-1

=x²-2x+1-2

=(x-1)²-2

=（√5+1-1）²-2

=5-2

=3