найдите значение выражения 2sin(a+3п)-2cos(-п/2+a)/5sin(a-2п)

\frac{2sin(a+ \pi ) - 2cos( \frac{- \pi }{2} + a )}{5sin(a)} = \frac{-2sin(a) - 2sin(a)}{5sin(a)} =\frac{-4sin(a)}{5sin(a)} = \frac{-4}{5} = -0.8