Possible Duplicate:
General::ivar is not a valid variable when plotting - what actually causes this and how to avoid it?
I need to define a function using the output of series, i.e.
f[x_,M_]:= Normal[Series[Sin[x],{x,0,M}]];
Now, for reasons explained in Normal[Series[ ]] does not give a normal expression that I can't fully understand (due inexperience and lack of time), the above code does not work as is.
I've managed to use f
within other functions, like
InverseLaplaceTransform[#,s,t] & @ f[s,M]
where M
is given, but failing when trying to evaluate, i.e.
In[1]:= f[x_,m_]:= Normal[Series[Sin[x],{x,0,m}]];
In[2]:= f[x,3]
Out[2]= x - x^3/6
In[3]:= f[2,3]
General::ivar: 2 is not a valid variable. >>
General::ivar: 2 is not a valid variable. >>
Out[3]= Sin[2]
In a nutshell, is there a way to use f
like a "normal" function?
M=4
or 5 to say something. I thought it was implied in the context ofSeries
, silly me. $\endgroup$f[3,3]
fails with...". this would make it easier to locate (this is a common problem, so others will definitely have the same question) $\endgroup$