Помогите решить 11 . 12 в 12 u=1/6

Решите задачу:

$b_{n}=496*( \frac{1}{2}) ^{n}\\\\ b_{1}=496* \frac{1}{2} =248\\\\ b_{6} =496*( \frac{1}{2}) ^{6} =496* \frac{1}{64} =7,75\\\\S _{6} = \frac{ b_{6}*q- b_{1} }{q-1}\\\\ b_{6}= b_{1}* q^{5}\\\\ q^{5}= \frac{ b_{6} }{ b_{1} }= \frac{7,75}{248}=0,03125\\\\q= \sqrt[5]{0,03125} =$ $=0,5 S_{6}= \frac{7,75*0,5-248}{0,5-1}= \frac{3,875-248}{-0,5}=$ $= \frac{-244,125}{-0,5} =488,25\\\\\\( \frac{q}{4v}- \frac{v}{q} )* \frac{2}{q-2v}=$ $= \frac{ q^{2} -4 v^{2} }{4qv} * \frac{2}{q-2v} = \frac{(q-2v)(q+2v)}{2qv}* \frac{1}{q-2v} = \frac{q+2v}{2qv} = \frac{ \frac{1}{5}+2* \frac{1}{6} }{2* \frac{1}{5}* \frac{1}{6} }= \frac{ \frac{1}{5}+ \frac{1}{3} }{ \frac{1}{15} }= \frac{ \frac{8}{15} }{ \frac{1}{15}} =$ $=8$