Z=(a+bi)/(c+di) = (ac - bd)+ (ad + bc)i
|Z| ^2= (ac-bd)^2 + (ad + bc)^2 = (a^2 +b^2 )(c^2 + d^2)
所以 |Z| = 根号下【(a^2 +b^2 )(c^2 + d^2)】
Z=(a+bi)/(c+di) = (ac - bd)+ (ad + bc)i
|Z| ^2= (ac-bd)^2 + (ad + bc)^2 = (a^2 +b^2 )(c^2 + d^2)
所以 |Z| = 根号下【(a^2 +b^2 )(c^2 + d^2)】