Răspuns:
Explicație pas cu pas:
[tex]a=\sqrt{\dfrac{1}{1}+\dfrac{1}{7}+\dfrac{1}{2}+\dfrac{1}{7}+\dfrac{1}{3}+\dfrac{1}{7} +\dfrac{1}{4}+\dfrac{1}{7}+...+\dfrac{1}{252}+\dfrac{1}{7}-(1+\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{252})} =\\=\sqrt{252*\dfrac{1}{7}+(1+\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{252})-(1+\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{252}) }=\sqrt{36}=6.[/tex]
