Graficas y ecuaciones- Manipulate

Manipulate[Plot[a Cos[w x+d],{x,0,6}],{a,.1,3},{w,0,10}, {d,-2,2}]

Oscilador armonico con forzamiento

Manipulate[Show[ParametricPlot[Evaluate[First[{x[t],y[t]}/.NDSolve[{x'[t]==y[t],y'[t]==-x[t]+0.5 Cos[w t],Thread[{x[0],y[0]}==point]},{x,y},{t,0,T}]]],{t,0,T},PlotStyle->Red]],{w,.5,2},{{T,20},1,100},{{point,{3,0}},Locator},SaveDefinitions->True]

Manipulate[Show[Plot[Evaluate[First[{x[t],y[t]}/.NDSolve[{x'[t]==y[t],y'[t]==-x[t]+0.5 Cos[w t],Thread[{x[0],y[0]}==point]},{t,x},{t,0,T}]]],{t,0,T},PlotStyle->Red]],{w,.5,2},{{T,20},1,200},{{point,{3,0}},Locator},SaveDefinitions->True]

Pendulo con longitud variable

Manipulate[Show[ParametricPlot[Evaluate[First[{x[t],y[t]}/.NDSolve[{x'[t]==y[t],y'[t]==-x[t]*(1+e*Sin[w t]),Thread[{x[0],y[0]}==point]},{x,y},{t,0,T}]]],{t,0,T},PlotStyle->Red]],{{e,0.1},0,2},{w,.1,2},{{T,20},1,100},{{point,{3,0}},Locator},SaveDefinitions->True]

Manipulate[Show[Plot[Evaluate[First[{x[t],y[t]}/.NDSolve[{x'[t]==y[t],y'[t]==-x[t]*(1+e*Sin[w t]),Thread[{x[0],y[0]}==point]},{t,x},{t,0,T}]]],{t,0,T},PlotStyle->Red]],{{e,0.1},0,2},{w,0,2},{{T,20},1,200},{{point,{3,0}},Locator},SaveDefinitions->True]