Question

Fie numerele a=√2-1 si b=√2+1.
a) calculati a•b si a^2+b^2

Answer 1

a*b=(rad2-1)(rad2+1)
a*b=2-1
a*b=1

formula folosita :
(a+b)(a-b)=a^2-b^2

a^2+b^2=(rad2-1)^2+(rad2+1)^2=2-2rad2+1+2+2rad2+1=6