Use Manipulate to create an interactive plot that shows the parametrically-defined curve described by {x[t], y[t]} = {t Sin[t], t^2/15} for {t,0,10} along with a point of tangency, tangent vector, and tangent line to the curve for any choice of t between 0 and 10.
Clear[t, x, y, P, velvector, vel, scalefactor];
scalefactor = 0.5;
P[t_] = {t Sin[t], t^2/15};
curveplot = ParametricPlot[P[t], {t,0,10}, PlotStyle -> Thickness[0.01],
AxesLabel -> {"x", "y","z"}];
vel[t_] = D[P[t], t];
velvector[t_] := Vector[vel[t], Tail -> P[t], VectorColor -> Red, ScaleFactor
-> scalefactor];
Manipulate[Show[curveplot, velvector[t],{t,0,10}, PlotRange -> All]]
Something not right here, it failed.

Manipulate(see the documentation)? Is it how to plot a point, line, and vector on top of a graph (construct the objects using math and useGraphicsto make the pictures, then useShow: see the docs)? Is it how to make a parametric plot to begin with (use the docs)? Be specific, and show your work. – march Jun 28 '16 at 02:37Showcontents must be wrapped in{}likeShow[{(*your content goes here*)}]. Also, I don't think you needTablewrapped aroundvalvector[t]function. – e.doroskevic Jun 28 '16 at 15:47Table[]? – Feyre Jun 28 '16 at 15:49curveplotis not a function oft; there is a syntax error inTable. I cannot help more since I don't understand what you are trying to do. – anderstood Jun 28 '16 at 16:50