Question

P.A: Décimo termo: a1= √2 razão: -1/2

Answer 1

$a_1= \sqrt{2} \\ r=-\frac{1}{2}\\ \\ a_{10}=a_1+9.r\\ \\ a_{10}=\sqrt{2}+9.(-\frac{1}{2})\\ \\ \boxed{a_{10}= \sqrt{2} -\frac{9}{2}}$