June 19th, 2009, 08:36 PM  #1 
Newbie Joined: Jun 2009 Posts: 6 Thanks: 0  Calculator Question
Hello, Does anyone know of a calculator, preferably online, that will calculate to at least 50 or so decimal places? I would like to convert phi to a base 12 number with at least 45 duodecimal places. I've done some searching, but I still haven't found a calculator that is better than the Windows calculator which calculates to about 30 decimal places. Thank you. 
June 19th, 2009, 08:47 PM  #2 
Global Moderator Joined: Nov 2006 From: UTC 5 Posts: 16,046 Thanks: 937 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms  Re: Calculator Question
Check my .sig. 
June 19th, 2009, 09:11 PM  #3 
Global Moderator Joined: Nov 2006 From: UTC 5 Posts: 16,046 Thanks: 937 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms  Re: Calculator Question
I hacked together some code for converting to duodecimal for you: Code: duodigit(n)=["0","1","2","3","4","5","6","7","8","9","A","B"][n+1] duoint(n)=my(out="");if(n<=0,return(if(n<0,concat("",duoint(n)),"0")));while(n>0,out=concat(duodigit(n%12),out);n\=12);out duodecimal(x)=my(out=duodigit(if(x<0,floor(x),floor(x))),k);if(x==floor(x),return(out));out=concat(out,".");k=floor(precision(x)*log(10)/log(12)2);for(i=1,k,x=(xfloor(x))*12;out=concat(out,duodigit(floor(x))));out Code: \p 100 Code: duodecimal((1 + sqrt(5))/2) 
June 19th, 2009, 09:43 PM  #4 
Newbie Joined: Jun 2009 Posts: 6 Thanks: 0  Re: Calculator Question
Thanks for the response! Unfortunately I don't have a computer that I can download PARI to. Would it be too much for me to ask for you to post phi in base 12 to however many places you can stand to calculate? Thanks again. 
June 19th, 2009, 10:05 PM  #5  
Global Moderator Joined: Nov 2006 From: UTC 5 Posts: 16,046 Thanks: 937 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms  Re: Calculator Question Quote:
Quote:
 
June 19th, 2009, 10:18 PM  #6 
Newbie Joined: Jun 2009 Posts: 6 Thanks: 0  Re: Calculator Question
Actually, I tried to download PARI but the install file is a GZ file which I can't open because I don't have WinZip. Eventually, I'll probably just buy WinZip so that I can install PARI. Thanks a ton for the file! That helps a lot. 
June 19th, 2009, 10:21 PM  #7  
Global Moderator Joined: Nov 2006 From: UTC 5 Posts: 16,046 Thanks: 937 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms  Re: Calculator Question Quote:
Pari/GP is *really* worth it. You have no idea how easy it makes questions like this.  
June 19th, 2009, 10:57 PM  #8 
Newbie Joined: Jun 2009 Posts: 6 Thanks: 0  Re: Calculator Question
Great; I got PARI installed now. I'm sure I'll have a bit of a learning curve to go through before I can really utilize the program but I know this will help me out with a lot of stuff. Thanks! 
June 19th, 2009, 11:15 PM  #9 
Newbie Joined: Jun 2009 Posts: 6 Thanks: 0  Re: Calculator Question
So, after I've defined the duodecimal function (or any function), is there any way to get PARI to retain the function after I close the program? It seems that it wipes out the function after I close PARI and reopen.

June 19th, 2009, 11:17 PM  #10  
Global Moderator Joined: Nov 2006 From: UTC 5 Posts: 16,046 Thanks: 937 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms  Re: Calculator Question Quote:
1+1 2^7+3/2 7%2 (the remainder of 7 when divided by 2) 10! Then you just pick up named functions that apply to you: isprime(3^494+2) zeta(3) factor(20!+1) Looping functions are also good: for(k=1,10,print(k)) sum(n=1,10,n^2) forprime(p=2,100,print1(p" ")) forstep(n=3,21,2,print1(n", "))  

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