Re: Transforming a polynomial into a trigonometric format tia sal2
- To: mathgroup at smc.vnet.net
- Subject: [mg88241] Re: Transforming a polynomial into a trigonometric format tia sal2
- From: Szabolcs Horvát <szhorvat at gmail.com>
- Date: Tue, 29 Apr 2008 06:50:07 -0400 (EDT)
- Organization: University of Bergen
- References: <fv42j9$5ui$1@smc.vnet.net>
ratullochjk2 at gmail.com wrote: > Transforming a polynomial into a trigonometric format tia sal2 > > Greetings All > > I'm using mathematica 6 and I have a polynomial and would like to > convert it into > a Trigonometric format. Is this possible? > > Example: > I have a polynomial > 0.00154991- 4.01371 x + 1.81197 x^2 + 8.00183 x^3 - 9.3462 x^4 > > How can I transform this into a trigonometric format > Example: > 0.00596679 Cos[6.98132 x] + 0.00358397 Cos[7.21403 x] + > 2.25013 Sin[0.232711 x] - 4.51511 Sin[0.465421 x] > > Note: these aren't correct answers I just wanted to include and > example Hello tia sal2, I am not sure I understand the question ... Is this what you mean? In[175]:= poly = 0.00154991 - 4.01371 x + 1.81197 x^2 + 8.00183 x^3 - 9.3462 x^4 Out[175]= 0.00154991- 4.01371 x + 1.81197 x^2 + 8.00183 x^3 - 9.3462 x^4 In[176]:= TrigReduce[poly /. x -> Cos[y]] Out[176]= -2.59729 + 1.98766 Cos[y] - 3.76711 Cos[2 y] + 2.00046 Cos[3 y] - 1.16828 Cos[4 y] Szabolcs