Stretto

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1 years, 69 days

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These are questions asked by Stretto

I'm trying to plot the fourier transform of a function(a sigmoid) and maple refuses to plot it. It seems to try to compute it symbolically then craps out because it can't reduce it to a computable form. Of course trying to do some type of numerical evaluation is impossible because it substitutes the numerical value for the transform variable.

S := x->erf(x):

plot(abs(fourier(S(x),x,w)),w=0..100):

Warning, unable to evaluate the function to numeric values in the region; see the plotting command's help page to ensure the calling sequence is correct

 

Just want to plot the transform, I do not understand why it is do difficult for maple to do numerically. It should fall back on a numerical routine instead of crapping out.

 

 

 

How does one sync two or more different animations? Ideally it would be something like display(..., synchronize=true)

Is there any way to automatically create a legend for a plot of a list of functions? The problem is, I'd rather not specify the legend and maple require the exact number so I cannot specify a generic length such as [1,2,3,4,5,6,7,8].

 

plot([f1(x), f2(x), f3(x), sin(x)*cos(x)*sin(3x^2 + cos(x))], x=1..34)

 

The point is that I do not want or care what the legend is(except the names shouldn't be long). I just want to be able to use it to select the plots easily and to be able to reference them(so the naming matters in that the order shoudl be obvious).

 

When I try to get a higher resolution plot using numpoints, the lines are jagged and look lower resolution.

plot(sin(x),x=-10..10,numpoints=3000,resolution=10000)plot(sin(x),x=-10..10,numpoints=400,resolution=10000)

 

You can see the difference, the first does not look anti-aliased whil ethe second does(although the 2nd looks far better on my comp)

with(inttrans):
sinc := x->piecewise(x = 0, 1, sin(Pi*x)/x/Pi):
S := x->sinc(x):
SE := x->sinc(x)*exp(-x^2):
plot(abs(fourier(SE(x),x,s)),s=0..5)

 

works fine for S but when trying to plot SE I get

Warning, unable to evaluate the function to numeric values in the region; see the plotting command's help page to ensure the calling sequence is correct

 

I simply want to plot the fourier transform of a function so I can see it's frequency response. Maple seems to be breaking for more complex functions. It seems to be doing this when it can't evaluate the function exactly, which I don't care for plots.

 

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