>> From: Jim Gunson
A student of mine mistakenly plotted an inequality:
> plot(((x-2)*(x+1)<0),x=-2..3,thickness=3);
Instead of an error message, Maple 6.1 produced a piecewise plot, with
height = 1, where the condition (x-2)*(x+1)<0 is true, 0 otherwise.
Treating TRUE as 1 and FALSE as 0, was unexpected. Note that multiplying
the inequality by 2 gives the same plot, adding to it leads to an error:
>plot(3*((x-2)*(x+1)<0),x=-2..3,thickness=3);
>plot(2+((x-2)*(x+1)<0),x=-2..3,thickness=3);
Another curiosity is in the limit below:
>limit((sqrt(x^2+25)-5)/x^2,x=0);
Maple gives 1/10, the correct answer. However, computing or plotting the
function for very small |x| leads to errors, due, presumably, to the way
floating point numbers are represented. What is curious to me is the way
this pathological behaviour sets in, with a quasi sine-like behaviour
with increasing amplitude.
>plot((sqrt(x^2+25)-5)/x^2,x=-0.000001..0.000001);
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