As a challenge problem.  At what x,y coordinate does circle B (radius r) make contact with circle A (radius R)?  Let's suppose the center of circle A is at (0,0).  The height circle B sits at, is d above the 0 x-axis. 

For example if a:=[3,3,1,5,7,8,5,4,4,4,4,3,9]

What is the simplest way, or alternate ways, to remove only one 4 for example from the dataset.

What value of 'a' gives the best fit for the line y=3x+a to pts[[3,4],[5,6],[21,16]] ?

I'm getting errors using LinearFit from the Statistics package but maybe I'm not using it right.

pts1 := Vector([3, 5, 21]);
pts2 := Vector([4, 6, 16]);

with(Statistics);
L := LinearFit(3*x+a, pts1, pts2, a);

Suppose we have functions dependent on certain variables.  I don't want the dependencies explicitly shown in the output.  How do I hide them?

For example

f(x)+f(x)^2-(diff(y(t), t)) = diff(y(t), t, t)
                         

I would like just f not f(x) and similarily just y instead of y(t) shown.

Why doesn't PlotVector plot the arrows all in one size?  (as seen in the Maple help page here)