Question

решите пааэжажажажажжжжжжжжжж​

Answer 1

$a_{n}=68\cdot\frac{(-1)^{n} }{n}\\\\a_{2}=68\cdot\frac{(-1)^{2} }{2}=34 \\\\a_{17} =68\cdot\frac{(-1)^{17} }{17}=-4\\\\a_{5}=68\cdot\frac{(-1)^{5} }{5}=-\frac{68}{5} \\\\a_{7}=68\cdot\frac{(-1)^{7} }{7} =-\frac{68}{7}\\\\Otvet:\boxed{\frac{68}{7}}$