My guess is that the paper is looking for the full series, as a summation. If that's the case, then it isn't implemented.
If it really is looking for an expansion up to some number of terms, just take (sin(x).series()/cos(x).series()).series() == tan(x).series(). Note that unlike Mathematica, SymPy does not automatically re-compute the series evaluation when you combine series expansions with other expressions---you need to call series() again. Aaron Meurer On Mon, Oct 21, 2013 at 1:21 PM, Pablo Puente <[email protected]> wrote: > Hi, > > I understand that series() supports unevaluated Taylor series setting > n=None. > > I am writing a Wester test case X3 that probably needs unevaluated Taylor > series; series(sin(x))/series(cos(x))==series(tan(x)) . In Mathematica > syntax: > In[10]:= (* Note: sin(x) = x - x^3/6 + x^5/120 - x^7/5040 + O(x^9) > cos(x) = 1 - x^2/2 + x^4/24 - x^6/720 + O(x^8) > tan(x) = x + x^3/3 + 2/15 x^5 + 17/315 x^7 + O(x^9) *) > 0. Second > > In[11]:= tsin = Series[Sin[x], {x, 0, 7}] > 0. Second > > 3 5 7 > x x x 8 > Out[11]= x - -- + --- - ---- + O[x] > 6 120 5040 > > In[12]:= tcos = Series[Cos[x], {x, 0, 7}] > 0. Second > > 2 4 6 > x x x 8 > Out[12]= 1 - -- + -- - --- + O[x] > 2 24 720 > In[13]:= (* Note that additional terms will be computed as needed *) > 0. Second > > In[14]:= tsin/tcos > 0.01 Second > > 3 5 7 > x 2 x 17 x 8 > Out[14]= x + -- + ---- + ----- + O[x] > 3 15 315 > > In[15]:= Series[Tan[x], {x, 0, 7}] > 0.01 Second > > 3 5 7 > x 2 x 17 x 8 > Out[15]= x + -- + ---- + ----- + O[x] > 3 15 315 > > if I try with Sympy series(sin(x), n=None)/series(cos(x), n=None)) I get > TypeError: unsupported operand type(s) for /: 'generator' and 'generator'. > > Is i use series(sin(x))/series(cos(x)) it returns (x - x**3/6 + x**5/120 + > O(x**6))/(1 - x**2/2 + x**4/24 + O(x**6)) > > Is the unevaluated Talyor series support incomplete or is there any other > way SymPy can implement this test case? > > Thanks, > Pablo Puente > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sympy. > For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. For more options, visit https://groups.google.com/groups/opt_out.
