Re: FindRoot vs Solve
- To: mathgroup at smc.vnet.net
- Subject: [mg22441] Re: [mg22427] FindRoot vs Solve
- From: "Benjamin A. Jacobson" <bjacobson at illumitech.com>
- Date: Wed, 8 Mar 2000 02:21:43 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
Your different forms get different results because they use different
initial guesses.
FindRoot[28. Cos[phi1 Degree] - 20. == 0, {phi1, 0.1/Degree, 0.1, 90.}]
gives the result you're looking for.
At 12:40 AM 3/1/00 -0500, you wrote:
>Why is FindRoot not able to solve an equation using "Degree"? Solve can do
>it.
>
>In[]=
>
>Solve[28. Cos[phi Degree] - 20. == 0, phi]
>FindRoot[28. Cos[phi1 Degree] - 20. == 0, {phi1, 0.1, 0.1, 90.}]
>
>Out[]=
>
>{{phi->-44.4153},{phi->44.4153}}
>{phi1->96.7112}
>
>Only the following statement gives the right result:
>
>In[]=
>FindRoot[28. Cos[phi2] - 20. == 0, {phi2, 0.1, 0.1, 90.}]
>Out[]=
>{phi2->0.775193}
>
>so long F. Mittermayr
>
>
>
>