Manipulate[
Show[
ParametricPlot[
{Cos[t],Sin[t]},{t,0,2 Pi},ImageSize->100,Ticks->{{-1,1},{-3,-2,-1,1,2,3}},PlotRange->{{-1,1},{-3,3}},AspectRatio->3
],
Graphics[
{
Opacity[1],
Red,
Line[{{0,0},{1,Tan[theta]}}],
Blue,
Line[{{1,0},{1,Tan[theta]}}]
}
]
],
{{theta,Pi/4},-Pi/2,3 Pi/2}]