Use of vpa results

Question

Dmytro 2011-11-1

Hello,

Using vpa, I can get, for example

>> p=vpa('1/3',50)
p =
0.33333333333333333333333333333333333333333333333333

However, when I try to use the obtained value, precision is lost:

>> vpa(p/3,50)
ans =
0.11111111111111111111111111111111

How can I manipulate with such results without loosing precision? I tried many methods, but no one works:(

Thank you very much for your help!

Dima

Dmytro 2011-11-1

I discovered, that problem can be solved by specifying first

digits(50)

Probably, it uses specified digits precision before using precision specified in vpa(...,50) in such cases.

Thank you for your answer, I found solution immediately after this!)

Answer 1

Walter Roberson 2011-11-1

I would experiment with

vpa(subs('P/3','P',p),50)

Also, perhaps

vpa(p/sym(3),50)

Dmytro 2011-11-1

Thank you for your answer. However, it does not work:( I will be very grateful for any further suggestions how to tackle this problem.