solve hangs on Arc Functions
- To: mathgroup at yoda.ncsa.uiuc.edu (mathgroup for mathematica)
- Subject: solve hangs on Arc Functions
- From: Steven Warwick <sdw at hpsadsdw.hp.com>
- Date: Wed, 5 Sep 90 9:11:48 PDT
There appears to be a bug in solve in which expressions
involving Arc Trig functions cause Mma to hang with no return...
***************** This hangs
In[3]:= ww==ArcCos[ (4-ts^2 wc^2)/ (4+ts^2 wc^2)]
2 2
4 - ts wc
Out[3]= ww == ArcCos[-----------]
2 2
4 + ts wc
In[4]:= Solve[%,wc]
*********** this doesn't **********
In[4]:= Cos[wt] == (4-ts^2 wc^2)/ (4+ts^2 wc^2)
2 2
4 - ts wc
Out[4]= Cos[wt] == -----------
2 2
4 + ts wc
In[5]:= Solve[%,wc]
Sqrt[4 - 4 Cos[wt]] Sqrt[4 - 4 Cos[wt]]
Out[5]= {{wc -> -----------------------}, {wc -> -(-----------------------)}}
2 2 2 2
Sqrt[ts + ts Cos[wt]] Sqrt[ts + ts Cos[wt]]
**********************************
Watch out.....
--
Steven Warwick
Hewlett-Packard
sdw at hpsad