Manipulate[
 Show[
  ParametricPlot[
   {m*n*Cos[t], m*(1 - n)*Sin[t]}, {t, 0.01, T}],
  Graphics[
   {Red, PointSize[Medium],
    Point[{m n Cos[T], m*(1 - n)*Sin[T]}],
    Point[{0, m*(1 - n)*Sin[T]*1/n}],
    Point[{m*n*Cos[T]*1/(1 - n), 0}],
    Text[Style["A", 20], {0, m*(1 - n)*Sin[T]*1/n - 0.2}],
    Text[Style["M", 20], {m n Cos[T], m*(1 - n)*Sin[T] - 0.2}],
    Text[Style["B", 20], {m*n*Cos[T]*1/(1 - n), -0.2}],


     Line[{{0, m*(1 - n)*Sin[T]*1/n}, {m*n*Cos[T]*1/(1 - n), 0}}]}
   ]
  ], {{m, 3, "Dlina AB"}, 1, 5}, {{n, 0.5, "Otnoshenie"}, 0.2,
  0.9}, {{T, 7, "Vremya"}, 0, 10}]