Question

若m为正实数且m-m分之一=3 则m方-m方分之一的值为多少

Answer 1

(m+1/m)^2=(m-1/m)^2+4*m*1/m=(m-1/m)^2+4=3^3+4=13

m+1/m=±√13

m^2-1/m^2=(m-1/m)(m+1/m)=±3√13