Radio active decay

> A:=3:r:=0.20:N:=0.005:Ndata:=10:

> noise:=N*rand(-100..100):

> ydata:=array(1..Ndata):
tdata:=array(1..Ndata):

> p:=t -> A*exp(-r*t):

> for i from 1 to Ndata do tdata[i]:=i: ydata[i]:=p(i)+noise(): od:

> save Ndata, tdata, ydata,`MiniGrant/Maple/dataset5.m`;

Error, could not open `MiniGrant/Maple/dataset5.m` for writing

> evalm(ydata);

> plot([tdata[n],ydata[n],n=1..Ndata],0..10,0..5,style=POINT);

>