Manipulate[  Plot[a Sin[b  x + c]+d,{x,-4,8},
                                   PlotRange -> {{-4,8},{-4,4}},
                                   GridLines -> Automatic,
                                   PlotStyle -> RGBColor[0.9,0.0,0.0]],
      {a,0.8,3,0.2},{b,1,4,0.2},{c,0.0,3.8,0.2},{d,0,2,0.2}]

Manipulate[  Plot[{Sin[ x + c*Pi],Sin[x],Sin[ x + c*Pi]+ Sin[x]},{x,-4,8},
                                   PlotRange -> {{-4,8},{-4,4}},
                                   GridLines -> Automatic,
                                   PlotStyle -> {RGBColor[1,0,0],RGBColor[1,0,0],RGBColor[0,0,1]}],
                                     {c,0.0,2,0.05}]