Re: Help needed in Mathematica

*To*: mathgroup at yoda.physics.unc.edu*Subject*: Re: Help needed in Mathematica*From*: yoda at ele.crl.melco.co.jp (Kiyoshi Yoda)*Date*: Wed, 29 Jun 94 16:51:09 JST

>I've been unsucessfuly in converting from -4 Cos[t] - 4 Sin[t] to >5.64 Cos[t + 3 Pi / 4]. > >Handling transcedental functions is one of the weak parts of Mathematica. >I appreciate any assistance on this problem. What about this? In[7]:= trigrule=a_ Cos[t_] + b_ Sin[t_]-> Sqrt[a^2+b^2] Cos[t+ArcTan[a/b]]; In[8]:= (-4 Cos[t] - 4 Sin[t]) /. trigrule Out[8]= Pi 4 Sqrt[2] Cos[-- + t] 4 Regards, -- Kiyoshi Yoda yoda at ele.crl.melco.co.jp Mitsubishi Electric Corp., Central Res. Lab. 8-1-1 Tsukaguchi Hommachi, Amagasaki 661 Japan