\[b_{1} = \frac{1}{16};\ \ b_{2};\ \ b_{3};\ \ b_{4};\ \ \ b_{5} = 16\]
\[b_{5} = b_{1} \cdot q^{4}\]
\[q^{4} = \frac{b_{5}}{b_{1}} = 16\ :\frac{1}{16} = 16 \cdot 16 =\]
\[= 4^{4}.\]
\[q = 4:\]
\[b_{2} = \frac{1}{16} \cdot 4 = \frac{1}{4};\]
\[b_{3} = \frac{1}{4} \cdot 4 = 1;\]
\[b_{4} = 1 \cdot 4 = 4.\]
\[q = - 4:\]
\[b_{2} = \frac{1}{16} \cdot ( - 4) = - \frac{1}{4};\]
\[b_{3} = - \frac{1}{4} \cdot ( - 4) = 1;\]
\[b_{4} = 1 \cdot ( - 4) = - 4.\]