Question

Cineva vreo idee la 260 si 261?
Urgent va rog :'(

Answer 1

260
 fie a= √(2+√3)
si b=√(2-√3)
atunci z= (a+bi)/ (a-bi)

 si z^4= (a+bi)^4/ (a-bi)^4
 iar
 | z^4|= |(a+b)^4|/| (a-bi)^4|= |a+bi|^4/ |a-bi|^4=    (a²+b²)²/ (a²+b²)²=1
raspuns corect , d


261

√(a²+b²) +a +bi=8+4i
 bi=4i⇒b=4
 
√(a²+b²) +a =8
√(a²+16) =8-a

a²+16=64-16a+a²
16a=64-16
a=4-1
 a=3

z= 3+4i
|z| =√(3²+4²)=5. raspuns corect c)