Answer
$a_1=4$
$a_2=-2\sqrt 2$
$a_3=2$
$a_4=-\sqrt 2$
$a_5=1$
Work Step by Step
$a_n=a_1r^{n-1}$
$a_1=4,~~r=-\frac{1}{\sqrt 2}$
$a_2=4(-\frac{1}{\sqrt 2})^{2-1}=4(-\frac{1}{\sqrt 2})=-\frac{4}{\sqrt 2}=-\frac{4}{\sqrt 2}\frac{\sqrt 2}{\sqrt 2}=-\frac{4\sqrt 2}{2}=-2\sqrt 2$
$a_3=4(-\frac{1}{\sqrt 2})^{3-1}=4(-\frac{1}{\sqrt 2})^2=4.\frac{1}{2}=2$
$a_4=4(-\frac{1}{\sqrt 2})^{3-1}=4(-\frac{1}{\sqrt 2})^3=-\frac{4}{2\sqrt 2}=-\frac{2}{\sqrt 2}\frac{\sqrt 2}{\sqrt 2}=-\frac{2\sqrt 2}{2}=-\sqrt 2$
$a_5=4(-\frac{1}{\sqrt 2})^{5-1}=4(-\frac{1}{\sqrt 2})^4=4.\frac{1}{4}=1$
