Question

已知m+m的负一次方等于3,求m的2次方+m的负2次方,m-m的负一次方,

Answer 1

m^2+m^(-2)=(m+m^(-1))^2-2=9-2=7

[m-m^(-1)]^2=[(m+m^(-1)]^2-4=9-4=5

m-m^(-1)=土根号5