Question

VA ROOOOOOG. DAAAAAAU COOOROOOAAAAAANAAAA PROOOMIIIIITTTT. VAAAAAA IMPLOOOOOOR. DAAAAU COOOROOAAANAAAAA PROOOMIIIITTT. VA IMPLOOOOR. VAAAAA ROOOOOOG MUUUUULT AMM NEVOOOIEEE URGEEEENT​

Answer 1

Explicație pas cu pas:

Deci amplificam peste tot cu conjugata și obținem : Sn=[√2-1/(√2+1)(√2-1)]+[√3-√2/(√3+√2)(√3-√2)]+.......+[√n-√(n-1)/(√n+√(n-1)(√n-√(n-1)]

Sn= √2-1/(√2²-1²)+√3-√2/(√3²-√2²)+...+√n-√(n-1)/(√n²-√(n-1)²)

Sn= √2-1/2-1+√3-√2/3-2+...+√n-√(n-1)/n-n+1

Sn= √2-1/1+√3-√2/1+...+√n-√(n-1)/1

Sn= √2-1+√3-√2+....+√n-√(n-1)

Sn= 1+√n

Sn<2008 => 1+√n<2008 => √n< 2007, n€N*

=> n=1936