Question

21...22 repede...va rog...

Answer 1

21. a.  √2=(√2 -1)+1=√2-1+1=√2 unde √2 -1∈R\Q si 1∈Q .

b.  2=(√2 +3)-(√2 +1)=√2 -√2 +3-1=2 unde √2 +3 ;√2 +1∈R\Q .

22. a.  a=1 -√2 si b=1 +√2 <=> a+b=2∈Q si ab=(1 -√2)·(1 +√2)=1-2=-1∈Q .

b.  a=2 -√2 si b=2 +√2 <=> a+b=4∈Q si ab=(2 -√2)·(2 +√2)=4-2=2∈Q .