Question 278874
You know that 
{{{(sin(x))^2+(cos(x))^2=1}}}
{{{(sin(x))^2+(0.29)^2=1}}}
{{{(sin(x))^2+(0.0841)=1}}}
{{{(sin(x))^2=0.9159}}}
{{{sin(x)=0 +- 0.957}}}
Since {{{-pi/2 < x < 0}}}, then
{{{sin(x)=-0.957}}}