Another Look at Series
Series[Sin[x],{x,0,10}]
Series[Cos[x],{x,0,10}]Did you notice even and odd functions at work?
Normal[Series[Exp[x],{x,0,10}]]The Normal command truncates the series so you can work with it.
evenpart[Exp,x] oddpart[Exp,x]
p=Plot[Exp[x],{x,-3,3},DisplayFunction->Identity];
pe=Plot[evenpart[Exp,x],{x,-3,3},DisplayFunction->Identity];
po=Plot[oddpart[Exp,x],{x,-3,3},DisplayFunction->Identity];
Show[p,pe,po,DisplayFunction->$DisplayFunction];
Series[Exp[x],{x,0,10}]
Series[evenpart[Exp,x],{x,0,10}]
Series[oddpart[Exp,x],{x,0,10}]
Now did you notice something?
Keep this in mind when we do orthogonal expansions!
Up to Even and Odd Functions