Yes, the number you pass to evalf is the digits of precision, like expr.evalf(100) for 100 digits.
Aaron Meurer On Friday, April 8, 2016, Amy Valhausen <[email protected]> wrote: > Hi Aaron thanks so much for the reply will try this! Is there any way to > get more than 15 digits of accuracy? > > On Thursday, April 7, 2016 at 6:19:14 PM UTC-6, Amy Valhausen wrote: >> >> Fibonacci Reverse Calculation? >> >> Hi All! >> >> I was reading Dr Knotts entries about Binets formula on his fibonacci page >> >> http://www.maths.surrey.ac.uk/hosted-sites/R.Knott/Fibonacci/fibFormula.html >> >> I entered the formula into an Excel spreadsheet to see how this would >> work ; >> >> Binet Formula >> Fib(n) = (1.6180339^n – (–0.6180339..)^n) / 2.236067977.. >> >> Its fascinating to see how I can enter any number for (n) and see the >> correct fibonacci number returned! >> >> I have a question though, I am a newbie computer programmer using >> VB and Python and my math skills are average at best but I am very >> interest and curious about math and especially fibonacci numbers! >> >> Say I wanted to reverse and change the process. >> >> I have a very large fibonacci number and I want to know what the >> fibonacci number is at a specified position BEFORE it, how would >> I compute this, what would the formula be? >> >> So for example I have the 301 st fibo number of ; >> >> 359579325206583560961765665172189099052367214309267232255589801 >> >> And I want to be able to find what the fibonacci value would be (n) >> numbers >> BEFORE this... so I might want to know what the fibo value would be 50 >> numbers before or the 251st fibo number. How would I do that? >> >> >> -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] > <javascript:_e(%7B%7D,'cvml','sympy%[email protected]');>. > To post to this group, send email to [email protected] > <javascript:_e(%7B%7D,'cvml','[email protected]');>. > Visit this group at https://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/637dc9eb-184d-41dd-b808-95d5ee378fee%40googlegroups.com > <https://groups.google.com/d/msgid/sympy/637dc9eb-184d-41dd-b808-95d5ee378fee%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6KC7M03mcp8UE2N0Lafgmi1etJ%2Bo%2BSyiqttfudhdMKTDA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
