Răspuns :
Răspuns:
[..]=-1
{...}= 3-√5
Explicație pas cu pas:
[2-√5]= 2+[-√5]
-√9=-3<-√5<-√4=-2
deci [-√5]=-3
atunci
[2-√5]=2-3=-1∈Z
{2-√5}=2-√5-[2-√5]= 2-√5-(-1)=2-√5+1=3-√5, ok pt ca ∈[0,1)
[tex]\it 4<5<9 \Rightarrow \sqrt4<\sqrt5<\sqrt9 \Rightarrow 2<\sqrt5<3|_{\cdot(-1)} \Rightarrow\\ \\ \Rightarrow-3<-\sqrt5<-2|_{+2} \Rightarrow-1<2-\sqrt5<0 \Rightarrow[2-\sqrt5]=-1[/tex]
[tex]\it \{2-\sqrt5\} =2-\sqrt5-[2-\sqrt5]=2-\sqrt5-(-1)=3-\sqrt5\approx3-2,236\Rightarrow\\ \\ \{2-\sqrt5\} \approx 0,76[/tex]