RE: Displaying many digits
- To: mathgroup at smc.vnet.net
- Subject: [mg40941] RE: [mg40933] Displaying many digits
- From: "Wolf, Hartmut" <Hartmut.Wolf at t-systems.com>
- Date: Fri, 25 Apr 2003 08:02:24 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
>-----Original Message----- >From: Stepan Yakovenko [mailto:yakovenko at ngs.ru] To: mathgroup at smc.vnet.net >Sent: Thursday, April 24, 2003 11:31 AM >To: mathgroup at smc.vnet.net >Subject: [mg40941] [mg40933] Displaying many digits > > >HI! > > And what if I want to see many BesselJ's digits ? > >In[2]:= N[BesselJ[1,3.],20] >Out[2]= 0.339059 > >-- >Best regards, > Stepan mailto:yakovenko at ngs.ru > > Stepan, what you tried didn't and couldn't work. Why? You put in a number of machine precision (3.). See: In[2]:= N[BesselJ[1, 3.], 20] Out[2]= 0.339059 In[3]:= % // Precision Out[3]= 16 16 here, should always warn you. N[..., 20] can't make it any better You may try In[4]:= BesselJ[1, 3.`20] Out[4]= 0.3390589585259364589 In[5]:= Precision[%, Round -> False] Out[5]= 18.7577 Not quite good enough to supply sufficient accuracy at output, but you are free to improve. If, however, you quest for an exact result In[6]:= BesselJ[1, 3] Out[6]= BesselJ[1, 3] You (seemingly) wouldn't get more, but In[7]:= N[%, 20] Out[7]= 0.33905895852593645893 In[8]:= Precision[%, Round -> False] Out[8]= 20. -- Hartmut Wolf