Question

已知X=根号3-根号2, 求X+1/X

Answer 1

x=√3-√2

1/x=1/(√3-√2)=(√3+√2)/[(√3-√2)√3+√2)]=(√3+√2)/(3-2)=√3+√2

x+1/x=√3-√2+√3+√2=2√3