Question

помогите решить 3 и 4 задания

Answer 1

3)
$x_{n} = \frac{n^2+1}{ \sqrt{n} } \\ \\ x_{1} = \frac{1^2+1}{ \sqrt{1} } =2 \\ \\ x_{2} = \frac{2^2+1}{ \sqrt{2} } = \frac{5}{ \sqrt{2} }$

и т. д.

4)
$S_{6} = \frac{2*(1- \frac{1}{64}) }{1- \frac{1}{2} } =4* \frac{63}{64} = \frac{63}{16} =3 \frac{15}{16}$