Question

Fie a =√7-√2 si b√7+√2 . aratati ca 1 supra a + 1 supra b apartine intervalului ( 4 supra 5 ; 6 supra 5 ) !!!!!!!!!!!!!!!!!!

Answer 1

1/a+1/b= 1/ (√7-√2) +1/(√7-√2)=(√7+√2)/(7-2)+ (√7-√2)/(7-2)= (2√7)/5=(√28)/5

4/5=(√16)/5<√28/5<(√36)/5=6/5 afdevarat